21320031013 has 2 divisors, whose sum is σ = 21320031014. Its totient is φ = 21320031012.

The previous prime is 21320030999. The next prime is 21320031071. The reversal of 21320031013 is 31013002312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21134472129 + 185558884 = 145377^2 + 13622^2 .

It is a cyclic number.

It is not a de Polignac number, because 21320031013 - 2⁵ = 21320030981 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21320038013) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10660015506 + 10660015507.

It is an arithmetic number, because the mean of its divisors is an integer number (10660015507).

Almost surely, 2^21320031013 is an apocalyptic number.

It is an amenable number.

21320031013 is a deficient number, since it is larger than the sum of its proper divisors (1).

21320031013 is an equidigital number, since it uses as much as digits as its factorization.

21320031013 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 108, while the sum is 16.

Adding to 21320031013 its reverse (31013002312), we get a palindrome (52333033325).

The spelling of 21320031013 in words is "twenty-one billion, three hundred twenty million, thirty-one thousand, thirteen".