9931997988 has 54 divisors (see below), whose sum is σ = 27595735622. Its totient is φ = 3009695040.

The previous prime is 9931997953. The next prime is 9931997993. The reversal of 9931997988 is 8897991399.

It can be written as a sum of positive squares in only one way, i.e., 5942559744 + 3989438244 = 77088^2 + 63162^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 1135681 + ... + 1144392.

Almost surely, 2^9931997988 is an apocalyptic number.

It is an amenable number.

9931997988 is an abundant number, since it is smaller than the sum of its proper divisors (17663737634).

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

9931997988 is a wasteful number, since it uses less digits than its factorization.

9931997988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2280105 (or 2280089 counting only the distinct ones).

The product of its digits is 79361856, while the sum is 72.

The square root of 9931997988 is about 99659.4099320280. The cubic root of 9931997988 is about 2149.5400485715.

The spelling of 9931997988 in words is "nine billion, nine hundred thirty-one million, nine hundred ninety-seven thousand, nine hundred eighty-eight".