31920340 has 24 divisors (see below), whose sum is σ = 67140360. Its totient is φ = 12747648.

The previous prime is 31920337. The next prime is 31920349. The reversal of 31920340 is 4302913.

It can be written as a sum of positive squares in 4 ways, for example, as 7772944 + 24147396 = 2788^2 + 4914^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31920349) 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, 20634 + ... + 22126.

It is an arithmetic number, because the mean of its divisors is an integer number (2797515).

Almost surely, 2^31920340 is an apocalyptic number.

It is an amenable number.

31920340 is an abundant number, since it is smaller than the sum of its proper divisors (35220020).

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

31920340 is a wasteful number, since it uses less digits than its factorization.

31920340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2571 (or 2569 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 22.

The square root of 31920340 is about 5649.8088463239. The cubic root of 31920340 is about 317.2165490556.

The spelling of 31920340 in words is "thirty-one million, nine hundred twenty thousand, three hundred forty".