31171920 has 160 divisors (see below), whose sum is σ = 106159872. Its totient is φ = 7520256.

The previous prime is 31171919. The next prime is 31171937. The reversal of 31171920 is 2917113.

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

It is a congruent number.

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 31 ways as a sum of consecutive naturals, for example, 302589 + ... + 302691.

Almost surely, 2^31171920 is an apocalyptic number.

31171920 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 31171920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (53079936).

31171920 is an abundant number, since it is smaller than the sum of its proper divisors (74987952).

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

31171920 is a wasteful number, since it uses less digits than its factorization.

31171920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 229 (or 223 counting only the distinct ones).

The product of its (nonzero) digits is 378, while the sum is 24.

The square root of 31171920 is about 5583.1818884933. The cubic root of 31171920 is about 314.7177113240.

The spelling of 31171920 in words is "thirty-one million, one hundred seventy-one thousand, nine hundred twenty".