21919768916399 has 2 divisors, whose sum is σ = 21919768916400. Its totient is φ = 21919768916398.

The previous prime is 21919768916321. The next prime is 21919768916417. The reversal of 21919768916399 is 99361986791912.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21919768916399 is a prime.

It is a super-2 number, since 2×21919768916399² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21919768916099) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10959884458199 + 10959884458200.

It is an arithmetic number, because the mean of its divisors is an integer number (10959884458200).

Almost surely, 2^{21919768916399} is an apocalyptic number.

21919768916399 is a deficient number, since it is larger than the sum of its proper divisors (1).

21919768916399 is an equidigital number, since it uses as much as digits as its factorization.

21919768916399 is an evil number, because the sum of its binary digits is even.

The product of its digits is 714256704, while the sum is 80.

The spelling of 21919768916399 in words is "twenty-one trillion, nine hundred nineteen billion, seven hundred sixty-eight million, nine hundred sixteen thousand, three hundred ninety-nine".