31521313432 has 32 divisors (see below), whose sum is σ = 67555274400. Its totient is φ = 13507213824.

The previous prime is 31521313337. The next prime is 31521313457. The reversal of 31521313432 is 23431312513.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a self number, because there is not a number n which added to its sum of digits gives 31521313432.

It is a congruent number.

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, 400294 + ... + 472522.

It is an arithmetic number, because the mean of its divisors is an integer number (2111102325).

Almost surely, 2^31521313432 is an apocalyptic number.

It is an amenable number.

31521313432 is an abundant number, since it is smaller than the sum of its proper divisors (36033960968).

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

31521313432 is a wasteful number, since it uses less digits than its factorization.

31521313432 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80035 (or 80031 counting only the distinct ones).

The product of its digits is 6480, while the sum is 28.

Adding to 31521313432 its reverse (23431312513), we get a palindrome (54952625945).

The spelling of 31521313432 in words is "thirty-one billion, five hundred twenty-one million, three hundred thirteen thousand, four hundred thirty-two".