66631256885 has 4 divisors (see below), whose sum is σ = 79957508268. Its totient is φ = 53305005504.

The previous prime is 66631256803. The next prime is 66631256891. The reversal of 66631256885 is 58865213666.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 13640137681 + 52991119204 = 116791^2 + 230198^2 .

It is a cyclic number.

It is not a de Polignac number, because 66631256885 - 2²⁸ = 66362821429 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 66631256885.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6663125684 + ... + 6663125693.

It is an arithmetic number, because the mean of its divisors is an integer number (19989377067).

Almost surely, 2^66631256885 is an apocalyptic number.

It is an amenable number.

66631256885 is a deficient number, since it is larger than the sum of its proper divisors (13326251383).

66631256885 is a wasteful number, since it uses less digits than its factorization.

66631256885 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13326251382.

The product of its digits is 12441600, while the sum is 56.

The spelling of 66631256885 in words is "sixty-six billion, six hundred thirty-one million, two hundred fifty-six thousand, eight hundred eighty-five".