31920420 has 48 divisors (see below), whose sum is σ = 102146688. Its totient is φ = 7296000.

The previous prime is 31920409. The next prime is 31920433. The reversal of 31920420 is 2402913.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 37581 + ... + 38420.

It is an arithmetic number, because the mean of its divisors is an integer number (2128056).

Almost surely, 2^31920420 is an apocalyptic number.

31920420 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

31920420 is an abundant number, since it is smaller than the sum of its proper divisors (70226268).

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

31920420 is a wasteful number, since it uses less digits than its factorization.

31920420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76020 (or 76018 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 21.

The square root of 31920420 is about 5649.8159262050. The cubic root of 31920420 is about 317.2168140622.

The spelling of 31920420 in words is "thirty-one million, nine hundred twenty thousand, four hundred twenty".