31681801656 has 96 divisors (see below), whose sum is σ = 87468825600. Its totient is φ = 10357588800.

The previous prime is 31681801649. The next prime is 31681801667. The reversal of 31681801656 is 65610818613.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 840445 + ... + 877331.

It is an arithmetic number, because the mean of its divisors is an integer number (911133600).

Almost surely, 2^31681801656 is an apocalyptic number.

31681801656 is a gapful number since it is divisible by the number (36) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31681801656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43734412800).

31681801656 is an abundant number, since it is smaller than the sum of its proper divisors (55787023944).

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

31681801656 is a wasteful number, since it uses less digits than its factorization.

31681801656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37129 (or 37122 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 45.

The spelling of 31681801656 in words is "thirty-one billion, six hundred eighty-one million, eight hundred one thousand, six hundred fifty-six".