31940640 has 144 divisors (see below), whose sum is σ = 111862296. Its totient is φ = 8294400.

The previous prime is 31940617. The next prime is 31940647. The reversal of 31940640 is 4604913.

31940640 is a `hidden beast` number, since 3 + 19 + 4 + 0 + 640 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 15586704 + 16353936 = 3948^2 + 4044^2 .

It is a tau number, because it is divible by the number of its divisors (144).

It is a nialpdrome in base 12.

It is not an unprimeable number, because it can be changed into a prime (31940647) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 58770 + ... + 59310.

Almost surely, 2^31940640 is an apocalyptic number.

31940640 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 31940640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (55931148).

31940640 is an abundant number, since it is smaller than the sum of its proper divisors (79921656).

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

31940640 is a wasteful number, since it uses less digits than its factorization.

31940640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 603 (or 592 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 27.

The square root of 31940640 is about 5651.6050817445. The cubic root of 31940640 is about 317.2837802875.

The spelling of 31940640 in words is "thirty-one million, nine hundred forty thousand, six hundred forty".