31396720 has 40 divisors (see below), whose sum is σ = 74977344. Its totient is φ = 12218112.

The previous prime is 31396709. The next prime is 31396727. The reversal of 31396720 is 2769313.

It is a tau number, because it is divible by the number of its divisors (40).

It is a hoax number, since the sum of its digits (31) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31396727) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2344 + ... + 8263.

Almost surely, 2^31396720 is an apocalyptic number.

It is an amenable number.

31396720 is an abundant number, since it is smaller than the sum of its proper divisors (43580624).

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

31396720 is a wasteful number, since it uses less digits than its factorization.

31396720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10657 (or 10651 counting only the distinct ones).

The product of its (nonzero) digits is 6804, while the sum is 31.

The square root of 31396720 is about 5603.2776122552. The cubic root of 31396720 is about 315.4724413195.

It can be divided in two parts, 31 and 396720, that multiplied together give a triangular number (12298320 = T₄₉₅₉).

The spelling of 31396720 in words is "thirty-one million, three hundred ninety-six thousand, seven hundred twenty".