18422209 has 4 divisors (see below), whose sum is σ = 19839316. Its totient is φ = 17005104.

The previous prime is 18422197. The next prime is 18422213. The reversal of 18422209 is 90222481.

18422209 = T₁₆₇₇ + T₁₆₇₈ + ... + T₁₆₈₉.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90222481 = 1579 ⋅57139.

It can be written as a sum of positive squares in 2 ways, for example, as 1587600 + 16834609 = 1260^2 + 4103^2 .

It is a cyclic number.

It is not a de Polignac number, because 18422209 - 2⁷ = 18422081 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18422249) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 708534 + ... + 708559.

It is an arithmetic number, because the mean of its divisors is an integer number (4959829).

Almost surely, 2^18422209 is an apocalyptic number.

It is an amenable number.

18422209 is a deficient number, since it is larger than the sum of its proper divisors (1417107).

18422209 is a wasteful number, since it uses less digits than its factorization.

18422209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1417106.

The product of its (nonzero) digits is 2304, while the sum is 28.

The square root of 18422209 is about 4292.1100871250. The cubic root of 18422209 is about 264.1073991017.

The spelling of 18422209 in words is "eighteen million, four hundred twenty-two thousand, two hundred nine".