31945040 has 80 divisors (see below), whose sum is σ = 79869888. Its totient is φ = 11839488.

The previous prime is 31945031. The next prime is 31945051. The reversal of 31945040 is 4054913.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 112739 + ... + 113021.

Almost surely, 2^31945040 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 31945040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39934944).

31945040 is an abundant number, since it is smaller than the sum of its proper divisors (47924848).

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

31945040 is a wasteful number, since it uses less digits than its factorization.

31945040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 396 (or 390 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 26.

The square root of 31945040 is about 5651.9943382845. The cubic root of 31945040 is about 317.2983488177.

Adding to 31945040 its reverse (4054913), we get a palindrome (35999953).

The spelling of 31945040 in words is "thirty-one million, nine hundred forty-five thousand, forty".