661682713056784 has 80 divisors (see below), whose sum is σ = 1399129213445568. Its totient is φ = 301918711320576.

The previous prime is 661682713056679. The next prime is 661682713056829. The reversal of 661682713056784 is 487650317286166.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 204869982 + ... + 208074685.

Almost surely, 2^{661682713056784} is an apocalyptic number.

It is an amenable number.

661682713056784 is an abundant number, since it is smaller than the sum of its proper divisors (737446500388784).

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

661682713056784 is a wasteful number, since it uses less digits than its factorization.

661682713056784 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 412944872 (or 412944866 counting only the distinct ones).

The product of its (nonzero) digits is 487710720, while the sum is 70.

The spelling of 661682713056784 in words is "six hundred sixty-one trillion, six hundred eighty-two billion, seven hundred thirteen million, fifty-six thousand, seven hundred eighty-four".