31497920 has 56 divisors (see below), whose sum is σ = 75492864. Its totient is φ = 12517376.

The previous prime is 31497883. The next prime is 31497929. The reversal of 31497920 is 2979413.

It is a hoax number, since the sum of its digits (35) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (31497929) 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 7 ways as a sum of consecutive naturals, for example, 82049 + ... + 82431.

Almost surely, 2^31497920 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 31497920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37746432).

31497920 is an abundant number, since it is smaller than the sum of its proper divisors (43994944).

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

31497920 is a wasteful number, since it uses less digits than its factorization.

31497920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 657 (or 647 counting only the distinct ones).

The product of its (nonzero) digits is 13608, while the sum is 35.

The square root of 31497920 is about 5612.3007759741. The cubic root of 31497920 is about 315.8110283923.

The spelling of 31497920 in words is "thirty-one million, four hundred ninety-seven thousand, nine hundred twenty".