31616917920 has 480 divisors, whose sum is σ = 128432304000. Its totient is φ = 7175153664.

The previous prime is 31616917901. The next prime is 31616917931. The reversal of 31616917920 is 2971961613.

31616917920 is a `hidden beast` number, since 3 + 1 + 616 + 9 + 1 + 7 + 9 + 20 = 666.

It is a tau number, because it is divible by the number of its divisors (480).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 13516111 + ... + 13518449.

It is an arithmetic number, because the mean of its divisors is an integer number (267567300).

Almost surely, 2^31616917920 is an apocalyptic number.

31616917920 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 31616917920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (64216152000).

31616917920 is an abundant number, since it is smaller than the sum of its proper divisors (96815386080).

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

31616917920 is a wasteful number, since it uses less digits than its factorization.

31616917920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2522 (or 2505 counting only the distinct ones).

The product of its (nonzero) digits is 122472, while the sum is 45.

The spelling of 31616917920 in words is "thirty-one billion, six hundred sixteen million, nine hundred seventeen thousand, nine hundred twenty".