6556620672666 has 24 divisors (see below), whose sum is σ = 14314454298144. Its totient is φ = 2168856710280.

The previous prime is 6556620672631. The next prime is 6556620672673. The reversal of 6556620672666 is 6662760266556.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1390290406 + ... + 1390295121.

It is an arithmetic number, because the mean of its divisors is an integer number (596435595756).

Almost surely, 2^{6556620672666} is an apocalyptic number.

6556620672666 is an abundant number, since it is smaller than the sum of its proper divisors (7757833625478).

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

6556620672666 is a wasteful number, since it uses less digits than its factorization.

6556620672666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2780585666 (or 2780585663 counting only the distinct ones).

The product of its (nonzero) digits is 195955200, while the sum is 63.

The spelling of 6556620672666 in words is "six trillion, five hundred fifty-six billion, six hundred twenty million, six hundred seventy-two thousand, six hundred sixty-six".