18220109 has 2 divisors, whose sum is σ = 18220110. Its totient is φ = 18220108.

The previous prime is 18220099. The next prime is 18220121. The reversal of 18220109 is 90102281.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18062500 + 157609 = 4250^2 + 397^2 .

It is an emirp because it is prime and its reverse (90102281) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18220109 - 2⁴ = 18220093 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18220159) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9110054 + 9110055.

It is an arithmetic number, because the mean of its divisors is an integer number (9110055).

Almost surely, 2^18220109 is an apocalyptic number.

It is an amenable number.

18220109 is a deficient number, since it is larger than the sum of its proper divisors (1).

18220109 is an equidigital number, since it uses as much as digits as its factorization.

18220109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 288, while the sum is 23.

The square root of 18220109 is about 4268.5019620471. The cubic root of 18220109 is about 263.1380529819.

The spelling of 18220109 in words is "eighteen million, two hundred twenty thousand, one hundred nine".