18921997754459 has 2 divisors, whose sum is σ = 18921997754460. Its totient is φ = 18921997754458.

The previous prime is 18921997754437. The next prime is 18921997754477. The reversal of 18921997754459 is 95445779912981.

It is a strong prime.

It is an emirp because it is prime and its reverse (95445779912981) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18921997754459 - 2³² = 18917702787163 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (18921997054459) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9460998877229 + 9460998877230.

It is an arithmetic number, because the mean of its divisors is an integer number (9460998877230).

Almost surely, 2^{18921997754459} is an apocalyptic number.

18921997754459 is a deficient number, since it is larger than the sum of its proper divisors (1).

18921997754459 is an equidigital number, since it uses as much as digits as its factorization.

18921997754459 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2057529600, while the sum is 80.

The spelling of 18921997754459 in words is "eighteen trillion, nine hundred twenty-one billion, nine hundred ninety-seven million, seven hundred fifty-four thousand, four hundred fifty-nine".