256641903 has 24 divisors (see below), whose sum is σ = 425536800. Its totient is φ = 146003904.

The previous prime is 256641883. The next prime is 256641941. The reversal of 256641903 is 309146652.

It is a happy number.

256641903 is a `hidden beast` number, since 2 + 5 + 6 + 641 + 9 + 0 + 3 = 666.

It is not a de Polignac number, because 256641903 - 2⁹ = 256641391 is a prime.

It is a super-2 number, since 2×256641903² = 131730132750922818, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256641403) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5533 + ... + 23321.

It is an arithmetic number, because the mean of its divisors is an integer number (17730700).

Almost surely, 2^256641903 is an apocalyptic number.

256641903 is a deficient number, since it is larger than the sum of its proper divisors (168894897).

256641903 is a wasteful number, since it uses less digits than its factorization.

256641903 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18031 (or 18028 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 36.

The square root of 256641903 is about 16020.0469100437. The cubic root of 256641903 is about 635.4906848632.

The spelling of 256641903 in words is "two hundred fifty-six million, six hundred forty-one thousand, nine hundred three".