31947640 has 16 divisors (see below), whose sum is σ = 71882280. Its totient is φ = 12779040.

The previous prime is 31947637. The next prime is 31947653. The reversal of 31947640 is 4674913.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 31947596 and 31947605.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 399306 + ... + 399385.

Almost surely, 2^31947640 is an apocalyptic number.

It is an amenable number.

31947640 is an abundant number, since it is smaller than the sum of its proper divisors (39934640).

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

31947640 is a wasteful number, since it uses less digits than its factorization.

31947640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 798702 (or 798698 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 34.

The square root of 31947640 is about 5652.2243409122. The cubic root of 31947640 is about 317.3069568658.

It can be divided in two parts, 319476 and 40, that multiplied together give a triangular number (12779040 = T₅₀₅₅).

The spelling of 31947640 in words is "thirty-one million, nine hundred forty-seven thousand, six hundred forty".