18511866427 has 2 divisors, whose sum is σ = 18511866428. Its totient is φ = 18511866426.

The previous prime is 18511866413. The next prime is 18511866509. The reversal of 18511866427 is 72466811581.

It is a weak prime.

It is an emirp because it is prime and its reverse (72466811581) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18511866427 is a prime.

It is a super-2 number, since 2×18511866427² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (18511866407) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9255933213 + 9255933214.

It is an arithmetic number, because the mean of its divisors is an integer number (9255933214).

Almost surely, 2^18511866427 is an apocalyptic number.

18511866427 is a deficient number, since it is larger than the sum of its proper divisors (1).

18511866427 is an equidigital number, since it uses as much as digits as its factorization.

18511866427 is an evil number, because the sum of its binary digits is even.

The product of its digits is 645120, while the sum is 49.

The spelling of 18511866427 in words is "eighteen billion, five hundred eleven million, eight hundred sixty-six thousand, four hundred twenty-seven".