31990440 has 32 divisors (see below), whose sum is σ = 95971680. Its totient is φ = 8530752.

The previous prime is 31990421. The next prime is 31990487. The reversal of 31990440 is 4409913.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 31990398 and 31990407.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 133174 + ... + 133413.

It is an arithmetic number, because the mean of its divisors is an integer number (2999115).

Almost surely, 2^31990440 is an apocalyptic number.

31990440 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

31990440 is an abundant number, since it is smaller than the sum of its proper divisors (63981240).

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

31990440 is a wasteful number, since it uses less digits than its factorization.

31990440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 266601 (or 266597 counting only the distinct ones).

The product of its (nonzero) digits is 3888, while the sum is 30.

The square root of 31990440 is about 5656.0091937690. The cubic root of 31990440 is about 317.4485915071.

The spelling of 31990440 in words is "thirty-one million, nine hundred ninety thousand, four hundred forty".