18226639 has 2 divisors, whose sum is σ = 18226640. Its totient is φ = 18226638.

The previous prime is 18226627. The next prime is 18226661. The reversal of 18226639 is 93662281.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18226639 - 2¹⁵ = 18193871 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 18226598 and 18226607.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18226679) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9113319 + 9113320.

It is an arithmetic number, because the mean of its divisors is an integer number (9113320).

Almost surely, 2^18226639 is an apocalyptic number.

18226639 is a deficient number, since it is larger than the sum of its proper divisors (1).

18226639 is an equidigital number, since it uses as much as digits as its factorization.

18226639 is an evil number, because the sum of its binary digits is even.

The product of its digits is 31104, while the sum is 37.

The square root of 18226639 is about 4269.2667988778. The cubic root of 18226639 is about 263.1694850341.

The spelling of 18226639 in words is "eighteen million, two hundred twenty-six thousand, six hundred thirty-nine".