31720940 has 48 divisors (see below), whose sum is σ = 68457312. Its totient is φ = 12343296.

The previous prime is 31720939. The next prime is 31720943. The reversal of 31720940 is 4902713.

It is not an unprimeable number, because it can be changed into a prime (31720943) 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, 160922 + ... + 161118.

It is an arithmetic number, because the mean of its divisors is an integer number (1426194).

Almost surely, 2^31720940 is an apocalyptic number.

It is an amenable number.

31720940 is an abundant number, since it is smaller than the sum of its proper divisors (36736372).

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

31720940 is a wasteful number, since it uses less digits than its factorization.

31720940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 386 (or 384 counting only the distinct ones).

The product of its (nonzero) digits is 1512, while the sum is 26.

The square root of 31720940 is about 5632.1345864601. The cubic root of 31720940 is about 316.5546393509.

The spelling of 31720940 in words is "thirty-one million, seven hundred twenty thousand, nine hundred forty".