18591636487213 has 2 divisors, whose sum is σ = 18591636487214. Its totient is φ = 18591636487212.

The previous prime is 18591636487133. The next prime is 18591636487271. The reversal of 18591636487213 is 31278463619581.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18591636487204 + 9 = 4311802^2 + 3^2 .

It is a cyclic number.

It is not a de Polignac number, because 18591636487213 - 2³³ = 18583046552621 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18591636487273) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9295818243606 + 9295818243607.

It is an arithmetic number, because the mean of its divisors is an integer number (9295818243607).

Almost surely, 2^{18591636487213} is an apocalyptic number.

It is an amenable number.

18591636487213 is a deficient number, since it is larger than the sum of its proper divisors (1).

18591636487213 is an equidigital number, since it uses as much as digits as its factorization.

18591636487213 is an evil number, because the sum of its binary digits is even.

The product of its digits is 52254720, while the sum is 64.

The spelling of 18591636487213 in words is "eighteen trillion, five hundred ninety-one billion, six hundred thirty-six million, four hundred eighty-seven thousand, two hundred thirteen".