18444809 has 2 divisors, whose sum is σ = 18444810. Its totient is φ = 18444808.

The previous prime is 18444791. The next prime is 18444823. The reversal of 18444809 is 90844481.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11580409 + 6864400 = 3403^2 + 2620^2 .

It is a cyclic number.

It is not a de Polignac number, because 18444809 - 2²⁰ = 17396233 is a prime.

It is not a weakly prime, because it can be changed into another prime (18444889) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9222404 + 9222405.

It is an arithmetic number, because the mean of its divisors is an integer number (9222405).

Almost surely, 2^18444809 is an apocalyptic number.

It is an amenable number.

18444809 is a deficient number, since it is larger than the sum of its proper divisors (1).

18444809 is an equidigital number, since it uses as much as digits as its factorization.

18444809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 36864, while the sum is 38.

The square root of 18444809 is about 4294.7420178632. The cubic root of 18444809 is about 264.2153555375.

The spelling of 18444809 in words is "eighteen million, four hundred forty-four thousand, eight hundred nine".