21797739919 has 2 divisors, whose sum is σ = 21797739920. Its totient is φ = 21797739918.

The previous prime is 21797739877. The next prime is 21797739923. The reversal of 21797739919 is 91993779712.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21797739919 - 2¹⁹ = 21797215631 is a prime.

It is a super-2 number, since 2×21797739919² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21797739619) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10898869959 + 10898869960.

It is an arithmetic number, because the mean of its divisors is an integer number (10898869960).

Almost surely, 2^21797739919 is an apocalyptic number.

21797739919 is a deficient number, since it is larger than the sum of its proper divisors (1).

21797739919 is an equidigital number, since it uses as much as digits as its factorization.

21797739919 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13502538, while the sum is 64.

The spelling of 21797739919 in words is "twenty-one billion, seven hundred ninety-seven million, seven hundred thirty-nine thousand, nine hundred nineteen".