18973199 has 4 divisors (see below), whose sum is σ = 21683664. Its totient is φ = 16262736.

The previous prime is 18973189. The next prime is 18973217. The reversal of 18973199 is 99137981.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 99137981 = 23 ⋅4310347.

It is not a de Polignac number, because 18973199 - 2²⁰ = 17924623 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18973159) 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, 1355222 + ... + 1355235.

It is an arithmetic number, because the mean of its divisors is an integer number (5420916).

Almost surely, 2^18973199 is an apocalyptic number.

18973199 is a deficient number, since it is larger than the sum of its proper divisors (2710465).

18973199 is an equidigital number, since it uses as much as digits as its factorization.

18973199 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2710464.

The product of its digits is 122472, while the sum is 47.

The square root of 18973199 is about 4355.8235731030. The cubic root of 18973199 is about 266.7146394596.

The spelling of 18973199 in words is "eighteen million, nine hundred seventy-three thousand, one hundred ninety-nine".