251081166400 has 63 divisors (see below), whose sum is σ = 617865917809. Its totient is φ = 100424449280.

The previous prime is 251081166377. The next prime is 251081166407. The reversal of 251081166400 is 4661180152.

The square root of 251081166400 is 501080.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 90389219904 + 160691946496 = 300648^2 + 400864^2 .

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (251081166407) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 20036937 + ... + 20049463.

Almost surely, 2^251081166400 is an apocalyptic number.

251081166400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

251081166400 is the 501080-th square number.

It is an amenable number.

251081166400 is an abundant number, since it is smaller than the sum of its proper divisors (366784751409).

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

251081166400 is an frugal number, since it uses more digits than its factorization.

251081166400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25076 (or 12534 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 34.

The spelling of 251081166400 in words is "two hundred fifty-one billion, eighty-one million, one hundred sixty-six thousand, four hundred".