31387696213 has 4 divisors (see below), whose sum is σ = 31391173900. Its totient is φ = 31384218528.

The previous prime is 31387696201. The next prime is 31387696229. The reversal of 31387696213 is 31269678313.

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 28231728529 + 3155967684 = 168023^2 + 56178^2 .

It is a cyclic number.

It is not a de Polignac number, because 31387696213 - 2⁹ = 31387695701 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31387696273) 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, 1725270 + ... + 1743367.

It is an arithmetic number, because the mean of its divisors is an integer number (7847793475).

Almost surely, 2^31387696213 is an apocalyptic number.

It is an amenable number.

31387696213 is a deficient number, since it is larger than the sum of its proper divisors (3477687).

31387696213 is an equidigital number, since it uses as much as digits as its factorization.

31387696213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3477686.

The product of its digits is 979776, while the sum is 49.

The spelling of 31387696213 in words is "thirty-one billion, three hundred eighty-seven million, six hundred ninety-six thousand, two hundred thirteen".