31000920 has 64 divisors (see below), whose sum is σ = 95286240. Its totient is φ = 8064000.

The previous prime is 31000903. The next prime is 31000927. The reversal of 31000920 is 2900013.

It is a super-2 number, since 2×31000920² = 1922114081692800, 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 31000920.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31000927) by changing a digit.

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, 1770 + ... + 8070.

Almost surely, 2^31000920 is an apocalyptic number.

31000920 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 31000920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (47643120).

31000920 is an abundant number, since it is smaller than the sum of its proper divisors (64285320).

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

31000920 is a wasteful number, since it uses less digits than its factorization.

31000920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6356 (or 6352 counting only the distinct ones).

The product of its (nonzero) digits is 54, while the sum is 15.

The square root of 31000920 is about 5567.8469806560. The cubic root of 31000920 is about 314.1411728108.

Adding to 31000920 its reverse (2900013), we get a palindrome (33900933).

The spelling of 31000920 in words is "thirty-one million, nine hundred twenty", and thus it is an aban number.