18444889 has 2 divisors, whose sum is σ = 18444890. Its totient is φ = 18444888.

The previous prime is 18444887. The next prime is 18444929. The reversal of 18444889 is 98844481.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16540489 + 1904400 = 4067^2 + 1380^2 .

It is a cyclic number.

It is not a de Polignac number, because 18444889 - 2¹ = 18444887 is a prime.

Together with 18444887, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18444887) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9222444 + 9222445.

It is an arithmetic number, because the mean of its divisors is an integer number (9222445).

Almost surely, 2^18444889 is an apocalyptic number.

It is an amenable number.

18444889 is a deficient number, since it is larger than the sum of its proper divisors (1).

18444889 is an equidigital number, since it uses as much as digits as its factorization.

18444889 is an evil number, because the sum of its binary digits is even.

The product of its digits is 294912, while the sum is 46.

The square root of 18444889 is about 4294.7513315674. The cubic root of 18444889 is about 264.2157375275.

The spelling of 18444889 in words is "eighteen million, four hundred forty-four thousand, eight hundred eighty-nine".