18944621 has 2 divisors, whose sum is σ = 18944622. Its totient is φ = 18944620.

The previous prime is 18944609. The next prime is 18944623. The reversal of 18944621 is 12644981.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12888100 + 6056521 = 3590^2 + 2461^2 .

It is a cyclic number.

It is not a de Polignac number, because 18944621 - 2²² = 14750317 is a prime.

Together with 18944623, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18944623) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9472310 + 9472311.

It is an arithmetic number, because the mean of its divisors is an integer number (9472311).

Almost surely, 2^18944621 is an apocalyptic number.

It is an amenable number.

18944621 is a deficient number, since it is larger than the sum of its proper divisors (1).

18944621 is an equidigital number, since it uses as much as digits as its factorization.

18944621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13824, while the sum is 35.

The square root of 18944621 is about 4352.5419010045. The cubic root of 18944621 is about 266.5806609796.

The spelling of 18944621 in words is "eighteen million, nine hundred forty-four thousand, six hundred twenty-one".