diff --git a/Cargo.toml b/Cargo.toml
index 8cdfc04167d..a5e6ee8da85 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -687,7 +687,6 @@ should_panic_without_expect = "allow"        # 2
 doc_markdown = "allow"
 unused_self = "allow"
 enum_glob_use = "allow"
-unreadable_literal = "allow"
 unnested_or_patterns = "allow"
 implicit_hasher = "allow"
 struct_field_names = "allow"
diff --git a/src/uucore/src/lib/features/format/num_format.rs b/src/uucore/src/lib/features/format/num_format.rs
index da263ad96eb..9a09b3f7dec 100644
--- a/src/uucore/src/lib/features/format/num_format.rs
+++ b/src/uucore/src/lib/features/format/num_format.rs
@@ -1127,11 +1127,11 @@ mod test {
                 ForceDecimal::No,
             )
         };
-        assert_eq!(f(0.1171875), "0.117188");
-        assert_eq!(f(0.01171875), "0.0117188");
-        assert_eq!(f(0.001171875), "0.00117187");
-        assert_eq!(f(0.0001171875), "0.000117187");
-        assert_eq!(f(0.001171875001), "0.00117188");
+        assert_eq!(f(0.117_187_5), "0.117188");
+        assert_eq!(f(0.011_718_75), "0.0117188");
+        assert_eq!(f(0.001_171_875), "0.00117187");
+        assert_eq!(f(0.000_117_187_5), "0.000117187");
+        assert_eq!(f(0.001_171_875_001), "0.00117188");
     }
 
     #[test]
@@ -1148,7 +1148,7 @@ mod test {
         assert_eq!(f(0.001), "0.001");
         assert_eq!(f(0.0001), "0.0001");
         assert_eq!(f(0.00001), "1e-05");
-        assert_eq!(f(0.000001), "1e-06");
+        assert_eq!(f(0.000_001), "1e-06");
     }
 
     /// Wrapper function to get a string out of Format.fmt()
diff --git a/src/uucore/src/lib/features/parser/num_parser.rs b/src/uucore/src/lib/features/parser/num_parser.rs
index b23f51fb52e..d690ec33f22 100644
--- a/src/uucore/src/lib/features/parser/num_parser.rs
+++ b/src/uucore/src/lib/features/parser/num_parser.rs
@@ -583,7 +583,7 @@ mod tests {
             u64::extended_parse("-9223372036854775808") // i64::MIN
         );
         assert_eq!(
-            Ok(1123372036854675616),
+            Ok(1_123_372_036_854_675_616),
             u64::extended_parse("-17323372036854876000") // 2*i64::MIN
         );
         assert_eq!(Ok(1), u64::extended_parse("-18446744073709551615")); // -u64::MAX
@@ -679,10 +679,10 @@ mod tests {
         assert_eq!(Ok(123.15), f64::extended_parse("0123.15"));
         assert_eq!(Ok(123.15), f64::extended_parse("+0123.15"));
         assert_eq!(Ok(-123.15), f64::extended_parse("-0123.15"));
-        assert_eq!(Ok(12315000.0), f64::extended_parse("123.15e5"));
-        assert_eq!(Ok(-12315000.0), f64::extended_parse("-123.15e5"));
-        assert_eq!(Ok(12315000.0), f64::extended_parse("123.15E+5"));
-        assert_eq!(Ok(0.0012315), f64::extended_parse("123.15E-5"));
+        assert_eq!(Ok(12_315_000.0), f64::extended_parse("123.15e5"));
+        assert_eq!(Ok(-12_315_000.0), f64::extended_parse("-123.15e5"));
+        assert_eq!(Ok(12_315_000.0), f64::extended_parse("123.15E+5"));
+        assert_eq!(Ok(0.001_231_5), f64::extended_parse("123.15E-5"));
         assert_eq!(
             Ok(0.15),
             f64::extended_parse(".150000000000000000000000000231313")
@@ -933,7 +933,7 @@ mod tests {
 
         // We cannot really check that 'e' is not a valid exponent indicator for hex floats...
         // but we can check that the number still gets parsed properly: 0x0.8e5 is 0x8e5 / 16**3
-        assert_eq!(Ok(0.555908203125), f64::extended_parse("0x0.8e5"));
+        assert_eq!(Ok(0.555_908_203_125), f64::extended_parse("0x0.8e5"));
 
         assert_eq!(
             f64::extended_parse("0x0.1p"),
diff --git a/src/uucore/src/lib/features/parser/parse_time.rs b/src/uucore/src/lib/features/parser/parse_time.rs
index 4abf85a1d4e..5435bd8231a 100644
--- a/src/uucore/src/lib/features/parser/parse_time.rs
+++ b/src/uucore/src/lib/features/parser/parse_time.rs
@@ -87,7 +87,7 @@ pub fn from_str(string: &str, allow_suffixes: bool) -> Result<Duration, String>
                 return Ok(Duration::MAX);
             }
             // early return if number is too small (< 1 ns)
-            if !bd.is_zero() && bd < bigdecimal::BigDecimal::from_f64(0.0000000001).unwrap() {
+            if !bd.is_zero() && bd < bigdecimal::BigDecimal::from_f64(0.000_000_000_1).unwrap() {
                 return Ok(NANOSECOND_DURATION);
             }
             bd
diff --git a/src/uucore/src/lib/features/sum.rs b/src/uucore/src/lib/features/sum.rs
index 0670bd50ea8..5272ab3c139 100644
--- a/src/uucore/src/lib/features/sum.rs
+++ b/src/uucore/src/lib/features/sum.rs
@@ -175,10 +175,10 @@ impl Crc {
         crc_fast::CrcParams::new(
             "CRC-32/CKSUM", // Name
             32,             // Width
-            0x04c11db7,     // Polynomial
-            0x00000000,     // Initial CRC value: 0 (not 0xffffffff)
+            0x04c1_1db7,    // Polynomial
+            0x0000_0000,    // Initial CRC value: 0 (not 0xffffffff)
             false,          // No input reflection (refin)
-            0xffffffff,     // XOR output with 0xffffffff (xorout)
+            0xffff_ffff,    // XOR output with 0xffffffff (xorout)
             0,              // Check value (not used)
         )
     }
@@ -245,7 +245,7 @@ impl Digest for CRC32B {
         let result = self.digest.finalize();
         // crc_fast returns a 64-bit value, but CRC32B should be 32-bit
         // Take the lower 32 bits and convert to big-endian bytes
-        let crc32_value = (result & 0xffffffff) as u32;
+        let crc32_value = (result & 0xffff_ffff) as u32;
         out.copy_from_slice(&crc32_value.to_be_bytes());
     }
 
@@ -601,7 +601,7 @@ mod tests {
         assert_ne!(empty_result, test_result);
 
         // Test known value: "test" should give 3076352578
-        assert_eq!(test_result, 3076352578);
+        assert_eq!(test_result, 3_076_352_578);
     }
 
     #[test]
@@ -653,9 +653,9 @@ mod tests {
         // Test against our CRC implementation values
         // Note: These are the correct values for our POSIX cksum implementation
         let test_cases = [
-            ("", 4294967295_u64),
-            ("a", 1220704766_u64),
-            ("abc", 1219131554_u64),
+            ("", 4_294_967_295_u64),
+            ("a", 1_220_704_766_u64),
+            ("abc", 1_219_131_554_u64),
         ];
 
         for (input, expected) in test_cases {
diff --git a/tests/by-util/test_dd.rs b/tests/by-util/test_dd.rs
index 7aaa90eb2d2..828a1e04311 100644
--- a/tests/by-util/test_dd.rs
+++ b/tests/by-util/test_dd.rs
@@ -1901,7 +1901,7 @@ fn test_skip_overflow() {
 #[cfg(target_os = "linux")]
 fn test_nocache_eof() {
     let (at, mut ucmd) = at_and_ucmd!();
-    at.write_bytes("in.f", &vec![0u8; 1234567]);
+    at.write_bytes("in.f", &vec![0u8; 1_234_567]);
     ucmd.args(&[
         "if=in.f",
         "of=out.f",
@@ -1910,7 +1910,7 @@ fn test_nocache_eof() {
         "status=noxfer",
     ])
     .succeeds();
-    assert_eq!(at.read_bytes("out.f").len(), 1234567);
+    assert_eq!(at.read_bytes("out.f").len(), 1_234_567);
 }
 
 #[test]
@@ -1918,7 +1918,7 @@ fn test_nocache_eof() {
 fn test_nocache_eof_fadvise_zero_length() {
     use std::process::Command;
     let (at, _ucmd) = at_and_ucmd!();
-    at.write_bytes("in.f", &vec![0u8; 1234567]);
+    at.write_bytes("in.f", &vec![0u8; 1_234_567]);
 
     let strace_file = at.plus_as_string("strace.out");
     let result = Command::new("strace")
diff --git a/tests/by-util/test_shred.rs b/tests/by-util/test_shred.rs
index a0aa7b505e8..81f69fb5c66 100644
--- a/tests/by-util/test_shred.rs
+++ b/tests/by-util/test_shred.rs
@@ -339,7 +339,7 @@ fn test_shred_non_utf8_paths() {
 fn test_gnu_shred_passes_20() {
     let (at, mut ucmd) = at_and_ucmd!();
 
-    let us_data = vec![0x55; 102400]; // 100K of 'U' bytes
+    let us_data = vec![0x55; 102_400]; // 100K of 'U' bytes
     at.write_bytes("Us", &us_data);
 
     let file = "f";
@@ -397,7 +397,7 @@ fn test_gnu_shred_passes_20() {
 fn test_gnu_shred_passes_different_counts() {
     let (at, mut ucmd) = at_and_ucmd!();
 
-    let us_data = vec![0x55; 102400];
+    let us_data = vec![0x55; 102_400];
     at.write_bytes("Us", &us_data);
 
     let file = "f";