18211859 has 2 divisors, whose sum is σ = 18211860. Its totient is φ = 18211858.

The previous prime is 18211819. The next prime is 18211877. The reversal of 18211859 is 95811281.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 18211859 - 2⁸ = 18211603 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18211819) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9105929 + 9105930.

It is an arithmetic number, because the mean of its divisors is an integer number (9105930).

Almost surely, 2^18211859 is an apocalyptic number.

18211859 is a deficient number, since it is larger than the sum of its proper divisors (1).

18211859 is an equidigital number, since it uses as much as digits as its factorization.

18211859 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5760, while the sum is 35.

The square root of 18211859 is about 4267.5354714402. The cubic root of 18211859 is about 263.0983309971.

The spelling of 18211859 in words is "eighteen million, two hundred eleven thousand, eight hundred fifty-nine".