31120920 has 96 divisors (see below), whose sum is σ = 102042720. Its totient is φ = 8225280.

The previous prime is 31120913. The next prime is 31120937. The reversal of 31120920 is 2902113.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 31120893 and 31120902.

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, 49005 + ... + 49635.

It is an arithmetic number, because the mean of its divisors is an integer number (1062945).

Almost surely, 2^31120920 is an apocalyptic number.

31120920 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 31120920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (51021360).

31120920 is an abundant number, since it is smaller than the sum of its proper divisors (70921800).

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

31120920 is a wasteful number, since it uses less digits than its factorization.

31120920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 785 (or 778 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 18.

The square root of 31120920 is about 5578.6127307781. The cubic root of 31120920 is about 314.5459823594.

The spelling of 31120920 in words is "thirty-one million, one hundred twenty thousand, nine hundred twenty".