18644917 has 2 divisors, whose sum is σ = 18644918. Its totient is φ = 18644916.

The previous prime is 18644911. The next prime is 18644921. The reversal of 18644917 is 71944681.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15952036 + 2692881 = 3994^2 + 1641^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18644917 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18644917.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18644911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9322458 + 9322459.

It is an arithmetic number, because the mean of its divisors is an integer number (9322459).

Almost surely, 2^18644917 is an apocalyptic number.

It is an amenable number.

18644917 is a deficient number, since it is larger than the sum of its proper divisors (1).

18644917 is an equidigital number, since it uses as much as digits as its factorization.

18644917 is an evil number, because the sum of its binary digits is even.

The product of its digits is 48384, while the sum is 40.

The square root of 18644917 is about 4317.9760305032. The cubic root of 18644917 is about 265.1674129051.

The spelling of 18644917 in words is "eighteen million, six hundred forty-four thousand, nine hundred seventeen".