31396440 has 32 divisors (see below), whose sum is σ = 94189680. Its totient is φ = 8372352.

The previous prime is 31396439. The next prime is 31396451. The reversal of 31396440 is 4469313.

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 = 31396398 and 31396407.

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 7 ways as a sum of consecutive naturals, for example, 130699 + ... + 130938.

Almost surely, 2^31396440 is an apocalyptic number.

31396440 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

31396440 is an abundant number, since it is smaller than the sum of its proper divisors (62793240).

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

31396440 is a wasteful number, since it uses less digits than its factorization.

31396440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 261651 (or 261647 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 30.

The square root of 31396440 is about 5603.2526268231. The cubic root of 31396440 is about 315.4715035088.

The spelling of 31396440 in words is "thirty-one million, three hundred ninety-six thousand, four hundred forty".