251353965978 has 12 divisors (see below), whose sum is σ = 544600259658. Its totient is φ = 83784655320.

The previous prime is 251353965971. The next prime is 251353965979. The reversal of 251353965978 is 879569353152.

It is a happy number.

251353965978 is a `hidden beast` number, since 2 + 5 + 1 + 3 + 5 + 39 + 6 + 597 + 8 = 666.

It can be written as a sum of positive squares in only one way, i.e., 149998966209 + 101354999769 = 387297^2 + 318363^2 .

It is not an unprimeable number, because it can be changed into a prime (251353965971) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6982054593 + ... + 6982054628.

Almost surely, 2^251353965978 is an apocalyptic number.

251353965978 is an abundant number, since it is smaller than the sum of its proper divisors (293246293680).

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

251353965978 is a wasteful number, since it uses less digits than its factorization.

251353965978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13964109229 (or 13964109226 counting only the distinct ones).

The product of its digits is 61236000, while the sum is 63.

The spelling of 251353965978 in words is "two hundred fifty-one billion, three hundred fifty-three million, nine hundred sixty-five thousand, nine hundred seventy-eight".