1048575

1048575 is a decimal integer equal to 2^20 − 1, the largest value representable by an unsigned 20-bit binary number. It is one less than 1,048,576, the power of two that marks a boundary in many computing contexts.

In binary, 1048575 is represented as 11111111111111111111, a string of twenty 1s. In other common bases, it is 0xFFFFF in hexadecimal and 0o3777777 in octal, reflecting its status as a full 20-bit set of ones.

The number is a binary repunit, since it equals 2^20 − 1. It is composite, and its prime factorization can be derived from 2^20 − 1 = (2^10 − 1)(2^10 + 1) = 1023 × 1025. Further factoring yields 1023 = 3 × 11 × 31 and 1025 = 5^2 × 41, so 1048575 = 3 × 5^2 × 11 × 31 × 41.

Due to its form, 1048575 often appears as a 20-bit bitmask of all ones, useful in low-level bitwise operations, masking, or as a boundary value in systems that use 20-bit addressing or storage. It also serves as a concrete example of a non-prime 2^n − 1 number when n is not prime.