251563435066 has 4 divisors (see below), whose sum is σ = 377345152602. Its totient is φ = 125781717532.

The previous prime is 251563435033. The next prime is 251563435073. The reversal of 251563435066 is 660534365152.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 231106140225 + 20457294841 = 480735^2 + 143029^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 62890858765 + ... + 62890858768.

Almost surely, 2^251563435066 is an apocalyptic number.

251563435066 is a deficient number, since it is larger than the sum of its proper divisors (125781717536).

251563435066 is a wasteful number, since it uses less digits than its factorization.

251563435066 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 125781717535.

The product of its (nonzero) digits is 1944000, while the sum is 46.

The spelling of 251563435066 in words is "two hundred fifty-one billion, five hundred sixty-three million, four hundred thirty-five thousand, sixty-six".