18420845 has 4 divisors (see below), whose sum is σ = 22105020. Its totient is φ = 14736672.

The previous prime is 18420817. The next prime is 18420863. The reversal of 18420845 is 54802481.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 11377129 + 7043716 = 3373^2 + 2654^2 .

It is a cyclic number.

It is not a de Polignac number, because 18420845 - 2²⁰ = 17372269 is a prime.

It is a congruent number.

It is an unprimeable number.

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 in 3 ways as a sum of consecutive naturals, for example, 1842080 + ... + 1842089.

It is an arithmetic number, because the mean of its divisors is an integer number (5526255).

Almost surely, 2^18420845 is an apocalyptic number.

It is an amenable number.

18420845 is a deficient number, since it is larger than the sum of its proper divisors (3684175).

18420845 is an equidigital number, since it uses as much as digits as its factorization.

18420845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3684174.

The product of its (nonzero) digits is 10240, while the sum is 32.

The square root of 18420845 is about 4291.9511879797. The cubic root of 18420845 is about 264.1008806764.

The spelling of 18420845 in words is "eighteen million, four hundred twenty thousand, eight hundred forty-five".