21016826917 has 2 divisors, whose sum is σ = 21016826918. Its totient is φ = 21016826916.

The previous prime is 21016826911. The next prime is 21016826933. The reversal of 21016826917 is 71962861012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12142056481 + 8874770436 = 110191^2 + 94206^2 .

It is a cyclic number.

It is not a de Polignac number, because 21016826917 - 2¹¹ = 21016824869 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21016826911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10508413458 + 10508413459.

It is an arithmetic number, because the mean of its divisors is an integer number (10508413459).

Almost surely, 2^21016826917 is an apocalyptic number.

It is an amenable number.

21016826917 is a deficient number, since it is larger than the sum of its proper divisors (1).

21016826917 is an equidigital number, since it uses as much as digits as its factorization.

21016826917 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72576, while the sum is 43.

The spelling of 21016826917 in words is "twenty-one billion, sixteen million, eight hundred twenty-six thousand, nine hundred seventeen".