66645665631 has 12 divisors (see below), whose sum is σ = 96281268408. Its totient is φ = 44423379024.

The previous prime is 66645665551. The next prime is 66645665701. The reversal of 66645665631 is 13656654666.

It is not a de Polignac number, because 66645665631 - 2³⁴ = 49465796447 is a prime.

It is a super-2 number, since 2×66645665631² (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 (66645675631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 528660 + ... + 642473.

It is an arithmetic number, because the mean of its divisors is an integer number (8023439034).

Almost surely, 2^66645665631 is an apocalyptic number.

66645665631 is a deficient number, since it is larger than the sum of its proper divisors (29635602777).

66645665631 is a wasteful number, since it uses less digits than its factorization.

66645665631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1177462 (or 1177459 counting only the distinct ones).

The product of its digits is 13996800, while the sum is 54.

The spelling of 66645665631 in words is "sixty-six billion, six hundred forty-five million, six hundred sixty-five thousand, six hundred thirty-one".