21021231013 has 2 divisors, whose sum is σ = 21021231014. Its totient is φ = 21021231012.

The previous prime is 21021230981. The next prime is 21021231019. The reversal of 21021231013 is 31013212012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20173373089 + 847857924 = 142033^2 + 29118^2 .

It is a cyclic number.

It is not a de Polignac number, because 21021231013 - 2⁵ = 21021230981 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21021231019) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510615506 + 10510615507.

It is an arithmetic number, because the mean of its divisors is an integer number (10510615507).

Almost surely, 2^21021231013 is an apocalyptic number.

It is an amenable number.

21021231013 is a deficient number, since it is larger than the sum of its proper divisors (1).

21021231013 is an equidigital number, since it uses as much as digits as its factorization.

21021231013 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72, while the sum is 16.

Adding to 21021231013 its reverse (31013212012), we get a palindrome (52034443025).

The spelling of 21021231013 in words is "twenty-one billion, twenty-one million, two hundred thirty-one thousand, thirteen".