31123320 has 64 divisors (see below), whose sum is σ = 93744000. Its totient is φ = 8266368.

The previous prime is 31123319. The next prime is 31123343. The reversal of 31123320 is 2332113.

It is a super-2 number, since 2×31123320² = 1937322095644800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 31123320.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 49971 + ... + 50589.

It is an arithmetic number, because the mean of its divisors is an integer number (1464750).

Almost surely, 2^31123320 is an apocalyptic number.

31123320 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

31123320 is an abundant number, since it is smaller than the sum of its proper divisors (62620680).

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

31123320 is a wasteful number, since it uses less digits than its factorization.

31123320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1052 (or 1048 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 15.

The square root of 31123320 is about 5578.8278338733. The cubic root of 31123320 is about 314.5540679275.

Adding to 31123320 its reverse (2332113), we get a palindrome (33455433).

The spelling of 31123320 in words is "thirty-one million, one hundred twenty-three thousand, three hundred twenty".