31997696640 has 512 divisors, whose sum is σ = 128478873600. Its totient is φ = 6592610304.

The previous prime is 31997696639. The next prime is 31997696651. The reversal of 31997696640 is 4669679913.

It is a Cunningham number, because it is equal to 178879²-1.

It is a Smith number, since the sum of its digits (60) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (60).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 7510831 + ... + 7515089.

It is an arithmetic number, because the mean of its divisors is an integer number (250935300).

Almost surely, 2^31997696640 is an apocalyptic number.

31997696640 is a gapful number since it is divisible by the number (30) 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 31997696640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (64239436800).

31997696640 is an abundant number, since it is smaller than the sum of its proper divisors (96481176960).

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

31997696640 is a wasteful number, since it uses less digits than its factorization.

31997696640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4344 (or 4332 counting only the distinct ones).

The product of its (nonzero) digits is 13226976, while the sum is 60.

The spelling of 31997696640 in words is "thirty-one billion, nine hundred ninety-seven million, six hundred ninety-six thousand, six hundred forty".