681636934644 has 24 divisors (see below), whose sum is σ = 1592587240608. Its totient is φ = 226912160160.

The previous prime is 681636934637. The next prime is 681636934661. The reversal of 681636934644 is 446439636186.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 37509462 + ... + 37527629.

It is an arithmetic number, because the mean of its divisors is an integer number (66357801692).

Almost surely, 2^681636934644 is an apocalyptic number.

It is an amenable number.

681636934644 is an abundant number, since it is smaller than the sum of its proper divisors (910950305964).

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

681636934644 is a wasteful number, since it uses less digits than its factorization.

681636934644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 75037855 (or 75037853 counting only the distinct ones).

The product of its digits is 53747712, while the sum is 60.

The spelling of 681636934644 in words is "six hundred eighty-one billion, six hundred thirty-six million, nine hundred thirty-four thousand, six hundred forty-four".