18209979 has 12 divisors (see below), whose sum is σ = 26344032. Its totient is φ = 12121200.

The previous prime is 18209977. The next prime is 18209981. The reversal of 18209979 is 97990281.

It is an interprime number because it is at equal distance from previous prime (18209977) and next prime (18209981).

It is not a de Polignac number, because 18209979 - 2¹ = 18209977 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18209977) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7089 + ... + 9309.

It is an arithmetic number, because the mean of its divisors is an integer number (2195336).

Almost surely, 2^18209979 is an apocalyptic number.

18209979 is a deficient number, since it is larger than the sum of its proper divisors (8134053).

18209979 is a wasteful number, since it uses less digits than its factorization.

18209979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3138 (or 3135 counting only the distinct ones).

The product of its (nonzero) digits is 81648, while the sum is 45.

The square root of 18209979 is about 4267.3151981076. The cubic root of 18209979 is about 263.0892775212.

The spelling of 18209979 in words is "eighteen million, two hundred nine thousand, nine hundred seventy-nine".