18808639 has 2 divisors, whose sum is σ = 18808640. Its totient is φ = 18808638.

The previous prime is 18808619. The next prime is 18808663. The reversal of 18808639 is 93680881.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18808639 - 2¹¹ = 18806591 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 18808595 and 18808604.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18808619) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9404319 + 9404320.

It is an arithmetic number, because the mean of its divisors is an integer number (9404320).

Almost surely, 2^18808639 is an apocalyptic number.

18808639 is a deficient number, since it is larger than the sum of its proper divisors (1).

18808639 is an equidigital number, since it uses as much as digits as its factorization.

18808639 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 82944, while the sum is 43.

The square root of 18808639 is about 4336.8927817044. The cubic root of 18808639 is about 265.9413018011.

The spelling of 18808639 in words is "eighteen million, eight hundred eight thousand, six hundred thirty-nine".