251261520164 has 12 divisors (see below), whose sum is σ = 441094752924. Its totient is φ = 125234447904.

The previous prime is 251261520071. The next prime is 251261520193. The reversal of 251261520164 is 461025162152.

It can be written as a sum of positive squares in 2 ways, for example, as 15057744100 + 236203776064 = 122710^2 + 486008^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 99076619 + ... + 99079154.

It is an arithmetic number, because the mean of its divisors is an integer number (36757896077).

Almost surely, 2^251261520164 is an apocalyptic number.

It is an amenable number.

251261520164 is a deficient number, since it is larger than the sum of its proper divisors (189833232760).

251261520164 is a wasteful number, since it uses less digits than its factorization.

251261520164 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 198156094 (or 198156092 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 35.

The spelling of 251261520164 in words is "two hundred fifty-one billion, two hundred sixty-one million, five hundred twenty thousand, one hundred sixty-four".