18009203 has 4 divisors (see below), whose sum is σ = 18630240. Its totient is φ = 17388168.

The previous prime is 18009197. The next prime is 18009223. The reversal of 18009203 is 30290081.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 30290081 = 509 ⋅59509.

It is not a de Polignac number, because 18009203 - 2²⁴ = 1231987 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18009223) 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, 310475 + ... + 310532.

It is an arithmetic number, because the mean of its divisors is an integer number (4657560).

Almost surely, 2^18009203 is an apocalyptic number.

18009203 is a deficient number, since it is larger than the sum of its proper divisors (621037).

18009203 is an equidigital number, since it uses as much as digits as its factorization.

18009203 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 621036.

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 18009203 is about 4243.7251324750. The cubic root of 18009203 is about 262.1187960390.

Adding to 18009203 its reverse (30290081), we get a palindrome (48299284).

The spelling of 18009203 in words is "eighteen million, nine thousand, two hundred three".