18219139 has 2 divisors, whose sum is σ = 18219140. Its totient is φ = 18219138.

The previous prime is 18219137. The next prime is 18219161. The reversal of 18219139 is 93191281.

It is a weak prime.

It is an emirp because it is prime and its reverse (93191281) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18219139 - 2¹ = 18219137 is a prime.

Together with 18219137, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (18219137) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9109569 + 9109570.

It is an arithmetic number, because the mean of its divisors is an integer number (9109570).

Almost surely, 2^18219139 is an apocalyptic number.

18219139 is a deficient number, since it is larger than the sum of its proper divisors (1).

18219139 is an equidigital number, since it uses as much as digits as its factorization.

18219139 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3888, while the sum is 34.

The square root of 18219139 is about 4268.3883375344. The cubic root of 18219139 is about 263.1333832615.

It can be divided in two parts, 182 and 19139, that added together give a square (19321 = 139²).

The spelling of 18219139 in words is "eighteen million, two hundred nineteen thousand, one hundred thirty-nine".