31513501321 has 4 divisors (see below), whose sum is σ = 31515063444. Its totient is φ = 31511939200.

The previous prime is 31513501249. The next prime is 31513501339. The reversal of 31513501321 is 12310531513.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 29783856400 + 1729644921 = 172580^2 + 41589^2 .

It is a cyclic number.

It is not a de Polignac number, because 31513501321 - 2⁷ = 31513501193 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31513501351) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 750400 + ... + 791281.

It is an arithmetic number, because the mean of its divisors is an integer number (7878765861).

Almost surely, 2^31513501321 is an apocalyptic number.

It is an amenable number.

31513501321 is a deficient number, since it is larger than the sum of its proper divisors (1562123).

31513501321 is a wasteful number, since it uses less digits than its factorization.

31513501321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1562122.

The product of its (nonzero) digits is 1350, while the sum is 25.

The spelling of 31513501321 in words is "thirty-one billion, five hundred thirteen million, five hundred one thousand, three hundred twenty-one".