21719322539 has 2 divisors, whose sum is σ = 21719322540. Its totient is φ = 21719322538.

The previous prime is 21719322511. The next prime is 21719322557. The reversal of 21719322539 is 93522391712.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21719322539 is a prime.

It is a super-2 number, since 2×21719322539² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21719322539.

It is not a weakly prime, because it can be changed into another prime (21719322589) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10859661269 + 10859661270.

It is an arithmetic number, because the mean of its divisors is an integer number (10859661270).

Almost surely, 2^21719322539 is an apocalyptic number.

21719322539 is a deficient number, since it is larger than the sum of its proper divisors (1).

21719322539 is an equidigital number, since it uses as much as digits as its factorization.

21719322539 is an evil number, because the sum of its binary digits is even.

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

The spelling of 21719322539 in words is "twenty-one billion, seven hundred nineteen million, three hundred twenty-two thousand, five hundred thirty-nine".