18555850811 has 2 divisors, whose sum is σ = 18555850812. Its totient is φ = 18555850810.

The previous prime is 18555850771. The next prime is 18555850861. The reversal of 18555850811 is 11805855581.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18555850811 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (18555850861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9277925405 + 9277925406.

It is an arithmetic number, because the mean of its divisors is an integer number (9277925406).

Almost surely, 2^18555850811 is an apocalyptic number.

18555850811 is a deficient number, since it is larger than the sum of its proper divisors (1).

18555850811 is an equidigital number, since it uses as much as digits as its factorization.

18555850811 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 320000, while the sum is 47.

The spelling of 18555850811 in words is "eighteen billion, five hundred fifty-five million, eight hundred fifty thousand, eight hundred eleven".