251220100566 has 16 divisors (see below), whose sum is σ = 514694840688. Its totient is φ = 81697593600.

The previous prime is 251220100529. The next prime is 251220100591. The reversal of 251220100566 is 665001022152.

It is a super-2 number, since 2×251220100566² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 510609715 + ... + 510610206.

It is an arithmetic number, because the mean of its divisors is an integer number (32168427543).

Almost surely, 2^251220100566 is an apocalyptic number.

251220100566 is an abundant number, since it is smaller than the sum of its proper divisors (263474740122).

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

251220100566 is a wasteful number, since it uses less digits than its factorization.

251220100566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1021219967.

The product of its (nonzero) digits is 7200, while the sum is 30.

The spelling of 251220100566 in words is "two hundred fifty-one billion, two hundred twenty million, one hundred thousand, five hundred sixty-six".