18228639 has 16 divisors (see below), whose sum is σ = 28554624. Its totient is φ = 10197600.

The previous prime is 18228601. The next prime is 18228649. The reversal of 18228639 is 93682281.

It is a happy number.

It is not a de Polignac number, because 18228639 - 2¹⁵ = 18195871 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a junction number, because it is equal to n+sod(n) for n = 18228597 and 18228606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18228649) 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 in 15 ways as a sum of consecutive naturals, for example, 20817 + ... + 21674.

It is an arithmetic number, because the mean of its divisors is an integer number (1784664).

Almost surely, 2^18228639 is an apocalyptic number.

18228639 is a deficient number, since it is larger than the sum of its proper divisors (10325985).

18228639 is a wasteful number, since it uses less digits than its factorization.

18228639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42518.

The product of its digits is 41472, while the sum is 39.

The square root of 18228639 is about 4269.5010247100. The cubic root of 18228639 is about 263.1791105008.

The spelling of 18228639 in words is "eighteen million, two hundred twenty-eight thousand, six hundred thirty-nine".