21038447738813 has 2 divisors, whose sum is σ = 21038447738814. Its totient is φ = 21038447738812.

The previous prime is 21038447738719. The next prime is 21038447738887. The reversal of 21038447738813 is 31883774483012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20631744359524 + 406703379289 = 4542218^2 + 637733^2 .

It is a cyclic number.

It is not a de Polignac number, because 21038447738813 - 2⁸ = 21038447738557 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21038447728813) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10519223869406 + 10519223869407.

It is an arithmetic number, because the mean of its divisors is an integer number (10519223869407).

Almost surely, 2^{21038447738813} is an apocalyptic number.

It is an amenable number.

21038447738813 is a deficient number, since it is larger than the sum of its proper divisors (1).

21038447738813 is an equidigital number, since it uses as much as digits as its factorization.

21038447738813 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 21676032, while the sum is 59.

The spelling of 21038447738813 in words is "twenty-one trillion, thirty-eight billion, four hundred forty-seven million, seven hundred thirty-eight thousand, eight hundred thirteen".