18219009 has 4 divisors (see below), whose sum is σ = 24292016. Its totient is φ = 12146004.

The previous prime is 18219001. The next prime is 18219017. The reversal of 18219009 is 90091281.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (18219001) and next prime (18219017).

It is not a de Polignac number, because 18219009 - 2³ = 18219001 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18219001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3036499 + ... + 3036504.

It is an arithmetic number, because the mean of its divisors is an integer number (6073004).

It is a Proth number, since it is equal to 139 ⋅ 2¹⁷ + 1 and 139 < 2¹⁷.

Almost surely, 2^18219009 is an apocalyptic number.

It is an amenable number.

18219009 is a deficient number, since it is larger than the sum of its proper divisors (6073007).

18219009 is an equidigital number, since it uses as much as digits as its factorization.

18219009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6073006.

The product of its (nonzero) digits is 1296, while the sum is 30.

The square root of 18219009 is about 4268.3731092771. The cubic root of 18219009 is about 263.1327574101.

It can be divided in two parts, 182 and 19009, that added together give a palindrome (19191).

The spelling of 18219009 in words is "eighteen million, two hundred nineteen thousand, nine".