251472820665 has 32 divisors (see below), whose sum is σ = 439835821056. Its totient is φ = 121675815360.

The previous prime is 251472820661. The next prime is 251472820681. The reversal of 251472820665 is 566028274152.

It is not a de Polignac number, because 251472820665 - 2² = 251472820661 is a prime.

It is a super-2 number, since 2×251472820665² (a number of 24 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (251472820661) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1484407 + ... + 1645116.

It is an arithmetic number, because the mean of its divisors is an integer number (13744869408).

Almost surely, 2^251472820665 is an apocalyptic number.

It is an amenable number.

251472820665 is a deficient number, since it is larger than the sum of its proper divisors (188363000391).

251472820665 is a wasteful number, since it uses less digits than its factorization.

251472820665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3130029.

The product of its (nonzero) digits is 1612800, while the sum is 48.

The spelling of 251472820665 in words is "two hundred fifty-one billion, four hundred seventy-two million, eight hundred twenty thousand, six hundred sixty-five".