18856369891 has 2 divisors, whose sum is σ = 18856369892. Its totient is φ = 18856369890.

The previous prime is 18856369849. The next prime is 18856369951. The reversal of 18856369891 is 19896365881.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18856369891 - 2¹¹ = 18856367843 is a prime.

It is a super-2 number, since 2×18856369891² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (18856363891) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9428184945 + 9428184946.

It is an arithmetic number, because the mean of its divisors is an integer number (9428184946).

Almost surely, 2^18856369891 is an apocalyptic number.

18856369891 is a deficient number, since it is larger than the sum of its proper divisors (1).

18856369891 is an equidigital number, since it uses as much as digits as its factorization.

18856369891 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 22394880, while the sum is 64.

The spelling of 18856369891 in words is "eighteen billion, eight hundred fifty-six million, three hundred sixty-nine thousand, eight hundred ninety-one".