31021872 has 80 divisors (see below), whose sum is σ = 96993792. Its totient is φ = 8340480.

The previous prime is 31021829. The next prime is 31021883. The reversal of 31021872 is 27812013.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2997 + ... + 8427.

Almost surely, 2^31021872 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31021872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (48496896).

31021872 is an abundant number, since it is smaller than the sum of its proper divisors (65971920).

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

31021872 is a wasteful number, since it uses less digits than its factorization.

31021872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5466 (or 5460 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 24.

The square root of 31021872 is about 5569.7281800820. The cubic root of 31021872 is about 314.2119277391.

Adding to 31021872 its reverse (27812013), we get a palindrome (58833885).

The spelling of 31021872 in words is "thirty-one million, twenty-one thousand, eight hundred seventy-two".