655660681561 has 8 divisors (see below), whose sum is σ = 671245324640. Its totient is φ = 640091344032.

The previous prime is 655660681541. The next prime is 655660681607. The reversal of 655660681561 is 165186066556.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 655660681561 - 2⁷ = 655660681433 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (655660681541) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3739671 + ... + 3911068.

It is an arithmetic number, because the mean of its divisors is an integer number (83905665580).

Almost surely, 2^655660681561 is an apocalyptic number.

It is an amenable number.

655660681561 is a deficient number, since it is larger than the sum of its proper divisors (15584643079).

655660681561 is a wasteful number, since it uses less digits than its factorization.

655660681561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7652775.

The product of its (nonzero) digits is 7776000, while the sum is 55.

The spelling of 655660681561 in words is "six hundred fifty-five billion, six hundred sixty million, six hundred eighty-one thousand, five hundred sixty-one".