18340639 has 2 divisors, whose sum is σ = 18340640. Its totient is φ = 18340638.

The previous prime is 18340631. The next prime is 18340709. The reversal of 18340639 is 93604381.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18340639 - 2³ = 18340631 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18340631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9170319 + 9170320.

It is an arithmetic number, because the mean of its divisors is an integer number (9170320).

Almost surely, 2^18340639 is an apocalyptic number.

18340639 is a deficient number, since it is larger than the sum of its proper divisors (1).

18340639 is an equidigital number, since it uses as much as digits as its factorization.

18340639 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15552, while the sum is 34.

The square root of 18340639 is about 4282.5972259833. The cubic root of 18340639 is about 263.7170167570.

The spelling of 18340639 in words is "eighteen million, three hundred forty thousand, six hundred thirty-nine".