66564644631 has 64 divisors (see below), whose sum is σ = 98051112960. Its totient is φ = 40007520000.

The previous prime is 66564644621. The next prime is 66564644651. The reversal of 66564644631 is 13644646566.

It is a happy number.

It is not a de Polignac number, because 66564644631 - 2¹¹ = 66564642583 is a prime.

It is a super-2 number, since 2×66564644631² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66564644621) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 63334056 + ... + 63335106.

It is an arithmetic number, because the mean of its divisors is an integer number (1532048640).

Almost surely, 2^66564644631 is an apocalyptic number.

66564644631 is a deficient number, since it is larger than the sum of its proper divisors (31486468329).

66564644631 is a wasteful number, since it uses less digits than its factorization.

66564644631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1668.

The product of its digits is 7464960, while the sum is 51.

The spelling of 66564644631 in words is "sixty-six billion, five hundred sixty-four million, six hundred forty-four thousand, six hundred thirty-one".