251651081205 has 32 divisors (see below), whose sum is σ = 453508206720. Its totient is φ = 132375358080.

The previous prime is 251651081189. The next prime is 251651081249. The reversal of 251651081205 is 502180156152.

251651081205 is a `hidden beast` number, since 2 + 5 + 16 + 510 + 8 + 120 + 5 = 666.

It is not a de Polignac number, because 251651081205 - 2⁴ = 251651081189 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 251651081205.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 12757831 + ... + 12777540.

It is an arithmetic number, because the mean of its divisors is an integer number (14172131460).

Almost surely, 2^251651081205 is an apocalyptic number.

It is an amenable number.

251651081205 is a deficient number, since it is larger than the sum of its proper divisors (201857125515).

251651081205 is a wasteful number, since it uses less digits than its factorization.

251651081205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25535458 (or 25535452 counting only the distinct ones).

The product of its (nonzero) digits is 24000, while the sum is 36.

The spelling of 251651081205 in words is "two hundred fifty-one billion, six hundred fifty-one million, eighty-one thousand, two hundred five".