18218365640399 has 2 divisors, whose sum is σ = 18218365640400. Its totient is φ = 18218365640398.

The previous prime is 18218365640383. The next prime is 18218365640429. The reversal of 18218365640399 is 99304656381281.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18218365640399 - 2⁴ = 18218365640383 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18218365640369) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9109182820199 + 9109182820200.

It is an arithmetic number, because the mean of its divisors is an integer number (9109182820200).

Almost surely, 2^{18218365640399} is an apocalyptic number.

18218365640399 is a deficient number, since it is larger than the sum of its proper divisors (1).

18218365640399 is an equidigital number, since it uses as much as digits as its factorization.

18218365640399 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 67184640, while the sum is 65.

The spelling of 18218365640399 in words is "eighteen trillion, two hundred eighteen billion, three hundred sixty-five million, six hundred forty thousand, three hundred ninety-nine".