661556051015464 has 16 divisors (see below), whose sum is σ = 1353182831622720. Its totient is φ = 300707295916080.

The previous prime is 661556051015443. The next prime is 661556051015507. The reversal of 661556051015464 is 464510150655166.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3758841198864 + ... + 3758841199039.

It is an arithmetic number, because the mean of its divisors is an integer number (84573926976420).

Almost surely, 2^{661556051015464} is an apocalyptic number.

It is an amenable number.

661556051015464 is an abundant number, since it is smaller than the sum of its proper divisors (691626780607256).

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

661556051015464 is a wasteful number, since it uses less digits than its factorization.

661556051015464 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7517682397920 (or 7517682397916 counting only the distinct ones).

The product of its (nonzero) digits is 12960000, while the sum is 55.

The spelling of 661556051015464 in words is "six hundred sixty-one trillion, five hundred fifty-six billion, fifty-one million, fifteen thousand, four hundred sixty-four".