66656561007 has 32 divisors (see below), whose sum is σ = 94146624000. Its totient is φ = 41832350208.

The previous prime is 66656560951. The next prime is 66656561053. The reversal of 66656561007 is 70016565666.

It is a happy number.

It is not a de Polignac number, because 66656561007 - 2¹⁶ = 66656495471 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66656561207) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 9717523 + ... + 9724379.

It is an arithmetic number, because the mean of its divisors is an integer number (2942082000).

Almost surely, 2^66656561007 is an apocalyptic number.

66656561007 is a deficient number, since it is larger than the sum of its proper divisors (27490062993).

66656561007 is a wasteful number, since it uses less digits than its factorization.

66656561007 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7935.

The product of its (nonzero) digits is 1360800, while the sum is 48.

The spelling of 66656561007 in words is "sixty-six billion, six hundred fifty-six million, five hundred sixty-one thousand, seven".