21313631291 has 2 divisors, whose sum is σ = 21313631292. Its totient is φ = 21313631290.

The previous prime is 21313631257. The next prime is 21313631333. The reversal of 21313631291 is 19213631312.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21313631291 is a prime.

It is not a weakly prime, because it can be changed into another prime (21313631791) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10656815645 + 10656815646.

It is an arithmetic number, because the mean of its divisors is an integer number (10656815646).

Almost surely, 2^21313631291 is an apocalyptic number.

21313631291 is a deficient number, since it is larger than the sum of its proper divisors (1).

21313631291 is an equidigital number, since it uses as much as digits as its factorization.

21313631291 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5832, while the sum is 32.

The spelling of 21313631291 in words is "twenty-one billion, three hundred thirteen million, six hundred thirty-one thousand, two hundred ninety-one".