66631556640 has 96 divisors (see below), whose sum is σ = 228970276416. Its totient is φ = 16153103360.

The previous prime is 66631556639. The next prime is 66631556701. The reversal of 66631556640 is 4665513666.

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 66631556640.

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 15 ways as a sum of consecutive naturals, for example, 6304527 + ... + 6315086.

It is an arithmetic number, because the mean of its divisors is an integer number (2385107046).

Almost surely, 2^66631556640 is an apocalyptic number.

66631556640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

66631556640 is an abundant number, since it is smaller than the sum of its proper divisors (162338719776).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66631556640 is a wasteful number, since it uses less digits than its factorization.

66631556640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12619642 (or 12619634 counting only the distinct ones).

The product of its (nonzero) digits is 2332800, while the sum is 48.

The spelling of 66631556640 in words is "sixty-six billion, six hundred thirty-one million, five hundred fifty-six thousand, six hundred forty".