31399872 has 112 divisors (see below), whose sum is σ = 96755712. Its totient is φ = 8801280.

The previous prime is 31399871. The next prime is 31399873. The reversal of 31399872 is 27899313.

It is an interprime number because it is at equal distance from previous prime (31399871) and next prime (31399873).

It is a tau number, because it is divible by the number of its divisors (112).

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31399871) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 81793 + ... + 82175.

Almost surely, 2^31399872 is an apocalyptic number.

31399872 is a gapful number since it is divisible by the number (32) 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 31399872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (48377856).

31399872 is an abundant number, since it is smaller than the sum of its proper divisors (65355840).

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

31399872 is a wasteful number, since it uses less digits than its factorization.

31399872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 466 (or 456 counting only the distinct ones).

The product of its digits is 81648, while the sum is 42.

The square root of 31399872 is about 5603.5588691474. The cubic root of 31399872 is about 315.4829980047.

The spelling of 31399872 in words is "thirty-one million, three hundred ninety-nine thousand, eight hundred seventy-two".