18898639 has 2 divisors, whose sum is σ = 18898640. Its totient is φ = 18898638.

The previous prime is 18898631. The next prime is 18898643. The reversal of 18898639 is 93689881.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 18898639 - 2³ = 18898631 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18898631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9449319 + 9449320.

It is an arithmetic number, because the mean of its divisors is an integer number (9449320).

Almost surely, 2^18898639 is an apocalyptic number.

18898639 is a deficient number, since it is larger than the sum of its proper divisors (1).

18898639 is an equidigital number, since it uses as much as digits as its factorization.

18898639 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 746496, while the sum is 52.

The square root of 18898639 is about 4347.2564911677. The cubic root of 18898639 is about 266.3648065209.

The spelling of 18898639 in words is "eighteen million, eight hundred ninety-eight thousand, six hundred thirty-nine".