18666499209 has 4 divisors (see below), whose sum is σ = 24888665616. Its totient is φ = 12444332804.

The previous prime is 18666499199. The next prime is 18666499249. The reversal of 18666499209 is 90299466681.

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: 90299466681 = 3 ⋅30099822227.

It is a cyclic number.

It is not a de Polignac number, because 18666499209 - 2⁴ = 18666499193 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18666499249) 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, 3111083199 + ... + 3111083204.

It is an arithmetic number, because the mean of its divisors is an integer number (6222166404).

Almost surely, 2^18666499209 is an apocalyptic number.

It is an amenable number.

18666499209 is a deficient number, since it is larger than the sum of its proper divisors (6222166407).

18666499209 is an equidigital number, since it uses as much as digits as its factorization.

18666499209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6222166406.

The product of its (nonzero) digits is 10077696, while the sum is 60.

The spelling of 18666499209 in words is "eighteen billion, six hundred sixty-six million, four hundred ninety-nine thousand, two hundred nine".