31997959518 has 48 divisors (see below), whose sum is σ = 74574998784. Its totient is φ = 9126215280.

The previous prime is 31997959507. The next prime is 31997959519. The reversal of 31997959518 is 81595979913.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31997959519) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 72571 + ... + 263177.

It is an arithmetic number, because the mean of its divisors is an integer number (1553645808).

Almost surely, 2^31997959518 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31997959518, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37287499392).

31997959518 is an abundant number, since it is smaller than the sum of its proper divisors (42577039266).

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

31997959518 is a wasteful number, since it uses less digits than its factorization.

31997959518 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 191197 (or 191190 counting only the distinct ones).

The product of its digits is 27556200, while the sum is 66.

The spelling of 31997959518 in words is "thirty-one billion, nine hundred ninety-seven million, nine hundred fifty-nine thousand, five hundred eighteen".