21179303917 has 2 divisors, whose sum is σ = 21179303918. Its totient is φ = 21179303916.

The previous prime is 21179303879. The next prime is 21179303939. The reversal of 21179303917 is 71930397112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12779398116 + 8399905801 = 113046^2 + 91651^2 .

It is a cyclic number.

It is not a de Polignac number, because 21179303917 - 2²⁷ = 21045086189 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21179303317) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10589651958 + 10589651959.

It is an arithmetic number, because the mean of its divisors is an integer number (10589651959).

Almost surely, 2^21179303917 is an apocalyptic number.

It is an amenable number.

21179303917 is a deficient number, since it is larger than the sum of its proper divisors (1).

21179303917 is an equidigital number, since it uses as much as digits as its factorization.

21179303917 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 71442, while the sum is 43.

The spelling of 21179303917 in words is "twenty-one billion, one hundred seventy-nine million, three hundred three thousand, nine hundred seventeen".