18169409 has 4 divisors (see below), whose sum is σ = 18185904. Its totient is φ = 18152916.

The previous prime is 18169387. The next prime is 18169427. The reversal of 18169409 is 90496181.

It is a happy number.

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, and also an emirpimes, since its reverse is a distinct semiprime: 90496181 = 1049 ⋅86269.

It is a cyclic number.

It is not a de Polignac number, because 18169409 - 2¹² = 18165313 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18169429) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6467 + ... + 8840.

It is an arithmetic number, because the mean of its divisors is an integer number (4546476).

Almost surely, 2^18169409 is an apocalyptic number.

It is an amenable number.

18169409 is a deficient number, since it is larger than the sum of its proper divisors (16495).

18169409 is a wasteful number, since it uses less digits than its factorization.

18169409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16494.

The product of its (nonzero) digits is 15552, while the sum is 38.

The square root of 18169409 is about 4262.5589731991. The cubic root of 18169409 is about 262.8937534382.

The spelling of 18169409 in words is "eighteen million, one hundred sixty-nine thousand, four hundred nine".