18505220169 has 4 divisors (see below), whose sum is σ = 24673626896. Its totient is φ = 12336813444.

The previous prime is 18505220143. The next prime is 18505220179. The reversal of 18505220169 is 96102250581.

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: 96102250581 = 3 ⋅32034083527.

It is not a de Polignac number, because 18505220169 - 2¹⁵ = 18505187401 is a prime.

It is a super-2 number, since 2×18505220169² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18505220179) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3084203359 + ... + 3084203364.

It is an arithmetic number, because the mean of its divisors is an integer number (6168406724).

Almost surely, 2^18505220169 is an apocalyptic number.

It is an amenable number.

18505220169 is a deficient number, since it is larger than the sum of its proper divisors (6168406727).

18505220169 is an equidigital number, since it uses as much as digits as its factorization.

18505220169 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6168406726.

The product of its (nonzero) digits is 43200, while the sum is 39.

The spelling of 18505220169 in words is "eighteen billion, five hundred five million, two hundred twenty thousand, one hundred sixty-nine".