21933540917 has 2 divisors, whose sum is σ = 21933540918. Its totient is φ = 21933540916.

The previous prime is 21933540877. The next prime is 21933540919. The reversal of 21933540917 is 71904533912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12492309361 + 9441231556 = 111769^2 + 97166^2 .

It is a cyclic number.

It is not a de Polignac number, because 21933540917 - 2⁸ = 21933540661 is a prime.

Together with 21933540919, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21933540919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10966770458 + 10966770459.

It is an arithmetic number, because the mean of its divisors is an integer number (10966770459).

Almost surely, 2^21933540917 is an apocalyptic number.

It is an amenable number.

21933540917 is a deficient number, since it is larger than the sum of its proper divisors (1).

21933540917 is an equidigital number, since it uses as much as digits as its factorization.

21933540917 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 204120, while the sum is 44.

The spelling of 21933540917 in words is "twenty-one billion, nine hundred thirty-three million, five hundred forty thousand, nine hundred seventeen".