256642398 has 32 divisors (see below), whose sum is σ = 571691520. Its totient is φ = 85341240.

The previous prime is 256642363. The next prime is 256642417. The reversal of 256642398 is 893246652.

256642398 is a `hidden beast` number, since 256 + 6 + 4 + 2 + 398 = 666.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17761 + ... + 28787.

It is an arithmetic number, because the mean of its divisors is an integer number (17865360).

Almost surely, 2^256642398 is an apocalyptic number.

256642398 is an abundant number, since it is smaller than the sum of its proper divisors (315049122).

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

256642398 is a wasteful number, since it uses less digits than its factorization.

256642398 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11469 (or 11463 counting only the distinct ones).

The product of its digits is 622080, while the sum is 45.

The square root of 256642398 is about 16020.0623594292. The cubic root of 256642398 is about 635.4910934321.

The spelling of 256642398 in words is "two hundred fifty-six million, six hundred forty-two thousand, three hundred ninety-eight".