256509635187 has 32 divisors (see below), whose sum is σ = 373867303936. Its totient is φ = 155481120000.

The previous prime is 256509635183. The next prime is 256509635209. The reversal of 256509635187 is 781536905652.

It is not a de Polignac number, because 256509635187 - 2² = 256509635183 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256509635183) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2078112 + ... + 2198082.

It is an arithmetic number, because the mean of its divisors is an integer number (11683353248).

Almost surely, 2^256509635187 is an apocalyptic number.

256509635187 is a deficient number, since it is larger than the sum of its proper divisors (117357668749).

256509635187 is a wasteful number, since it uses less digits than its factorization.

256509635187 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 120811.

The product of its (nonzero) digits is 13608000, while the sum is 57.

The spelling of 256509635187 in words is "two hundred fifty-six billion, five hundred nine million, six hundred thirty-five thousand, one hundred eighty-seven".