251036920881 has 12 divisors (see below), whose sum is σ = 369450563508. Its totient is φ = 164200249824.

The previous prime is 251036920837. The next prime is 251036920891. The reversal of 251036920881 is 188029630152.

251036920881 is a `hidden beast` number, since 2 + 5 + 1 + 0 + 369 + 208 + 81 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 194290534656 + 56746386225 = 440784^2 + 238215^2 .

It is not a de Polignac number, because 251036920881 - 2⁷ = 251036920753 is a prime.

It is a super-2 number, since 2×251036920881² (a number of 24 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (251036920811) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 263140950 + ... + 263141903.

It is an arithmetic number, because the mean of its divisors is an integer number (30787546959).

Almost surely, 2^251036920881 is an apocalyptic number.

It is an amenable number.

251036920881 is a deficient number, since it is larger than the sum of its proper divisors (118413642627).

251036920881 is a wasteful number, since it uses less digits than its factorization.

251036920881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 526282912 (or 526282909 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 45.

The spelling of 251036920881 in words is "two hundred fifty-one billion, thirty-six million, nine hundred twenty thousand, eight hundred eighty-one".