21331320013 has 2 divisors, whose sum is σ = 21331320014. Its totient is φ = 21331320012.

The previous prime is 21331319951. The next prime is 21331320047. The reversal of 21331320013 is 31002313312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21037471849 + 293848164 = 145043^2 + 17142^2 .

It is a cyclic number.

It is not a de Polignac number, because 21331320013 - 2¹³ = 21331311821 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21331320053) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10665660006 + 10665660007.

It is an arithmetic number, because the mean of its divisors is an integer number (10665660007).

Almost surely, 2^21331320013 is an apocalyptic number.

It is an amenable number.

21331320013 is a deficient number, since it is larger than the sum of its proper divisors (1).

21331320013 is an equidigital number, since it uses as much as digits as its factorization.

21331320013 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 324, while the sum is 19.

Adding to 21331320013 its reverse (31002313312), we get a palindrome (52333633325).

The spelling of 21331320013 in words is "twenty-one billion, three hundred thirty-one million, three hundred twenty thousand, thirteen".