18420811 has 2 divisors, whose sum is σ = 18420812. Its totient is φ = 18420810.

The previous prime is 18420791. The next prime is 18420817. The reversal of 18420811 is 11802481.

It is a strong prime.

It is an emirp because it is prime and its reverse (11802481) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18420811 - 2²³ = 10032203 is a prime.

It is not a weakly prime, because it can be changed into another prime (18420817) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9210405 + 9210406.

It is an arithmetic number, because the mean of its divisors is an integer number (9210406).

Almost surely, 2^18420811 is an apocalyptic number.

18420811 is a deficient number, since it is larger than the sum of its proper divisors (1).

18420811 is an equidigital number, since it uses as much as digits as its factorization.

18420811 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 512, while the sum is 25.

The square root of 18420811 is about 4291.9472270754. The cubic root of 18420811 is about 264.1007181895.

The spelling of 18420811 in words is "eighteen million, four hundred twenty thousand, eight hundred eleven".