18644449 has 2 divisors, whose sum is σ = 18644450. Its totient is φ = 18644448.

The previous prime is 18644443. The next prime is 18644459. The reversal of 18644449 is 94444681.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18490000 + 154449 = 4300^2 + 393^2 .

It is an emirp because it is prime and its reverse (94444681) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18644449 - 2³ = 18644441 is a prime.

It is not a weakly prime, because it can be changed into another prime (18644441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9322224 + 9322225.

It is an arithmetic number, because the mean of its divisors is an integer number (9322225).

Almost surely, 2^18644449 is an apocalyptic number.

It is an amenable number.

18644449 is a deficient number, since it is larger than the sum of its proper divisors (1).

18644449 is an equidigital number, since it uses as much as digits as its factorization.

18644449 is an evil number, because the sum of its binary digits is even.

The product of its digits is 110592, while the sum is 40.

The square root of 18644449 is about 4317.9218381068. The cubic root of 18644449 is about 265.1651942595.

The spelling of 18644449 in words is "eighteen million, six hundred forty-four thousand, four hundred forty-nine".