31320013520 has 40 divisors (see below), whose sum is σ = 72859577760. Its totient is φ = 12521029760.

The previous prime is 31320013519. The next prime is 31320013567. The reversal of 31320013520 is 2531002313.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 31320013492 and 31320013501.

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, 36791 + ... + 252969.

It is an arithmetic number, because the mean of its divisors is an integer number (1821489444).

Almost surely, 2^31320013520 is an apocalyptic number.

It is an amenable number.

31320013520 is an abundant number, since it is smaller than the sum of its proper divisors (41539564240).

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

31320013520 is a wasteful number, since it uses less digits than its factorization.

31320013520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 218003 (or 217997 counting only the distinct ones).

The product of its (nonzero) digits is 540, while the sum is 20.

Adding to 31320013520 its reverse (2531002313), we get a palindrome (33851015833).

The spelling of 31320013520 in words is "thirty-one billion, three hundred twenty million, thirteen thousand, five hundred twenty".