31398440 has 16 divisors (see below), whose sum is σ = 70646580. Its totient is φ = 12559360.

The previous prime is 31398407. The next prime is 31398457. The reversal of 31398440 is 4489313.

It can be written as a sum of positive squares in 2 ways, for example, as 30184036 + 1214404 = 5494^2 + 1102^2 .

It is a junction number, because it is equal to n+sod(n) for n = 31398397 and 31398406.

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 3 ways as a sum of consecutive naturals, for example, 392441 + ... + 392520.

Almost surely, 2^31398440 is an apocalyptic number.

It is an amenable number.

31398440 is an abundant number, since it is smaller than the sum of its proper divisors (39248140).

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

31398440 is a wasteful number, since it uses less digits than its factorization.

31398440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 784972 (or 784968 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 32.

The square root of 31398440 is about 5603.4310917508. The cubic root of 31398440 is about 315.4782020348.

The spelling of 31398440 in words is "thirty-one million, three hundred ninety-eight thousand, four hundred forty".