6561666220772 has 24 divisors (see below), whose sum is σ = 12575814014400. Its totient is φ = 2977131478176.

The previous prime is 6561666220763. The next prime is 6561666220783. The reversal of 6561666220772 is 2770226661656.

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, 1069368872 + ... + 1069375007.

It is an arithmetic number, because the mean of its divisors is an integer number (523992250600).

Almost surely, 2^{6561666220772} is an apocalyptic number.

It is an amenable number.

6561666220772 is a deficient number, since it is larger than the sum of its proper divisors (6014147793628).

6561666220772 is a wasteful number, since it uses less digits than its factorization.

6561666220772 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2138743955 (or 2138743953 counting only the distinct ones).

The product of its (nonzero) digits is 15240960, while the sum is 56.

The spelling of 6561666220772 in words is "six trillion, five hundred sixty-one billion, six hundred sixty-six million, two hundred twenty thousand, seven hundred seventy-two".