18219639 has 16 divisors (see below), whose sum is σ = 24727680. Its totient is φ = 11931360.

The previous prime is 18219623. The next prime is 18219647. The reversal of 18219639 is 93691281.

It is not a de Polignac number, because 18219639 - 2⁴ = 18219623 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 18219597 and 18219606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18219679) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 67597 + ... + 67865.

It is an arithmetic number, because the mean of its divisors is an integer number (1545480).

Almost surely, 2^18219639 is an apocalyptic number.

18219639 is a deficient number, since it is larger than the sum of its proper divisors (6508041).

18219639 is a wasteful number, since it uses less digits than its factorization.

18219639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 590.

The product of its digits is 23328, while the sum is 39.

The square root of 18219639 is about 4268.4469072486. The cubic root of 18219639 is about 263.1357903546.

The spelling of 18219639 in words is "eighteen million, two hundred nineteen thousand, six hundred thirty-nine".