18420559 has 2 divisors, whose sum is σ = 18420560. Its totient is φ = 18420558.

The previous prime is 18420533. The next prime is 18420581. The reversal of 18420559 is 95502481.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 18420559 - 2⁹ = 18420047 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18420659) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9210279 + 9210280.

It is an arithmetic number, because the mean of its divisors is an integer number (9210280).

Almost surely, 2^18420559 is an apocalyptic number.

18420559 is a deficient number, since it is larger than the sum of its proper divisors (1).

18420559 is an equidigital number, since it uses as much as digits as its factorization.

18420559 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 14400, while the sum is 34.

The square root of 18420559 is about 4291.9178696709. The cubic root of 18420559 is about 264.0995138689.

The spelling of 18420559 in words is "eighteen million, four hundred twenty thousand, five hundred fifty-nine".