18216821263 has 2 divisors, whose sum is σ = 18216821264. Its totient is φ = 18216821262.

The previous prime is 18216821213. The next prime is 18216821269. The reversal of 18216821263 is 36212861281.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 18216821263 - 2⁹ = 18216820751 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18216821269) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9108410631 + 9108410632.

It is an arithmetic number, because the mean of its divisors is an integer number (9108410632).

Almost surely, 2^18216821263 is an apocalyptic number.

18216821263 is a deficient number, since it is larger than the sum of its proper divisors (1).

18216821263 is an equidigital number, since it uses as much as digits as its factorization.

18216821263 is an evil number, because the sum of its binary digits is even.

The product of its digits is 55296, while the sum is 40.

The spelling of 18216821263 in words is "eighteen billion, two hundred sixteen million, eight hundred twenty-one thousand, two hundred sixty-three".