18978212247191 has 2 divisors, whose sum is σ = 18978212247192. Its totient is φ = 18978212247190.

The previous prime is 18978212247161. The next prime is 18978212247223. The reversal of 18978212247191 is 19174221287981.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18978212247191 - 2¹⁰ = 18978212246167 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18978212247131) 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, 9489106123595 + 9489106123596.

It is an arithmetic number, because the mean of its divisors is an integer number (9489106123596).

Almost surely, 2^{18978212247191} is an apocalyptic number.

18978212247191 is a deficient number, since it is larger than the sum of its proper divisors (1).

18978212247191 is an equidigital number, since it uses as much as digits as its factorization.

18978212247191 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8128512, while the sum is 62.

The spelling of 18978212247191 in words is "eighteen trillion, nine hundred seventy-eight billion, two hundred twelve million, two hundred forty-seven thousand, one hundred ninety-one".