18391936487 has 2 divisors, whose sum is σ = 18391936488. Its totient is φ = 18391936486.

The previous prime is 18391936441. The next prime is 18391936501. The reversal of 18391936487 is 78463919381.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 18391936487 - 2¹⁶ = 18391870951 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18391936427) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9195968243 + 9195968244.

It is an arithmetic number, because the mean of its divisors is an integer number (9195968244).

Almost surely, 2^18391936487 is an apocalyptic number.

18391936487 is a deficient number, since it is larger than the sum of its proper divisors (1).

18391936487 is an equidigital number, since it uses as much as digits as its factorization.

18391936487 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7838208, while the sum is 59.

The spelling of 18391936487 in words is "eighteen billion, three hundred ninety-one million, nine hundred thirty-six thousand, four hundred eighty-seven".