18791788821457 has 2 divisors, whose sum is σ = 18791788821458. Its totient is φ = 18791788821456.

The previous prime is 18791788821427. The next prime is 18791788821493. The reversal of 18791788821457 is 75412888719781.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9857333050321 + 8934455771136 = 3139639^2 + 2989056^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18791788821457 is a prime.

It is a super-2 number, since 2×18791788821457² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (18791788821427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9395894410728 + 9395894410729.

It is an arithmetic number, because the mean of its divisors is an integer number (9395894410729).

Almost surely, 2^{18791788821457} is an apocalyptic number.

It is an amenable number.

18791788821457 is a deficient number, since it is larger than the sum of its proper divisors (1).

18791788821457 is an equidigital number, since it uses as much as digits as its factorization.

18791788821457 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 505774080, while the sum is 76.

The spelling of 18791788821457 in words is "eighteen trillion, seven hundred ninety-one billion, seven hundred eighty-eight million, eight hundred twenty-one thousand, four hundred fifty-seven".