31388868 has 108 divisors (see below), whose sum is σ = 96550272. Its totient is φ = 8421120.

The previous prime is 31388849. The next prime is 31388869. The reversal of 31388868 is 86888313.

It is a super-2 number, since 2×31388868² = 1970522068642848, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31388869) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 72613 + ... + 73043.

It is an arithmetic number, because the mean of its divisors is an integer number (893984).

Almost surely, 2^31388868 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 31388868, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (48275136).

31388868 is an abundant number, since it is smaller than the sum of its proper divisors (65161404).

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

31388868 is a wasteful number, since it uses less digits than its factorization.

31388868 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 482 (or 460 counting only the distinct ones).

The product of its digits is 221184, while the sum is 45.

The square root of 31388868 is about 5602.5769071027. The cubic root of 31388868 is about 315.4461403117.

The spelling of 31388868 in words is "thirty-one million, three hundred eighty-eight thousand, eight hundred sixty-eight".