661156005056 has 28 divisors (see below), whose sum is σ = 1334218428840. Its totient is φ = 324974983680.

The previous prime is 661156005047. The next prime is 661156005073. The reversal of 661156005056 is 650500651166.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 87543365 + ... + 87550916.

Almost surely, 2^661156005056 is an apocalyptic number.

It is an amenable number.

661156005056 is an abundant number, since it is smaller than the sum of its proper divisors (673062423784).

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

661156005056 is a wasteful number, since it uses less digits than its factorization.

661156005056 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 175094352 (or 175094342 counting only the distinct ones).

The product of its (nonzero) digits is 162000, while the sum is 41.

The spelling of 661156005056 in words is "six hundred sixty-one billion, one hundred fifty-six million, five thousand, fifty-six".