21016325917 has 2 divisors, whose sum is σ = 21016325918. Its totient is φ = 21016325916.

The previous prime is 21016325909. The next prime is 21016325929. The reversal of 21016325917 is 71952361012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20235347001 + 780978916 = 142251^2 + 27946^2 .

It is a cyclic number.

It is not a de Polignac number, because 21016325917 - 2³ = 21016325909 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21016325987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10508162958 + 10508162959.

It is an arithmetic number, because the mean of its divisors is an integer number (10508162959).

Almost surely, 2^21016325917 is an apocalyptic number.

It is an amenable number.

21016325917 is a deficient number, since it is larger than the sum of its proper divisors (1).

21016325917 is an equidigital number, since it uses as much as digits as its factorization.

21016325917 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 22680, while the sum is 37.

Adding to 21016325917 its reverse (71952361012), we get a palindrome (92968686929).

The spelling of 21016325917 in words is "twenty-one billion, sixteen million, three hundred twenty-five thousand, nine hundred seventeen".