256657401 has 96 divisors (see below), whose sum is σ = 514375680. Its totient is φ = 118972800.

The previous prime is 256657393. The next prime is 256657421. The reversal of 256657401 is 104756652.

It is a happy number.

256657401 is a `hidden beast` number, since 2 + 566 + 57 + 40 + 1 = 666.

It is not a de Polignac number, because 256657401 - 2³ = 256657393 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (256657421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 278820 + ... + 279738.

It is an arithmetic number, because the mean of its divisors is an integer number (5358080).

Almost surely, 2^256657401 is an apocalyptic number.

256657401 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

256657401 is an abundant number, since it is smaller than the sum of its proper divisors (257718279).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

256657401 is a wasteful number, since it uses less digits than its factorization.

256657401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 987 (or 984 counting only the distinct ones).

The product of its (nonzero) digits is 50400, while the sum is 36.

The square root of 256657401 is about 16020.5306091902. The cubic root of 256657401 is about 635.5034765342.

The spelling of 256657401 in words is "two hundred fifty-six million, six hundred fifty-seven thousand, four hundred one".