18002002 has 4 divisors (see below), whose sum is σ = 27003006. Its totient is φ = 9001000.

The previous prime is 18001999. The next prime is 18002003. The reversal of 18002002 is 20020081.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 20020081 = 1933 ⋅10357.

It can be written as a sum of positive squares in only one way, i.e., 10055241 + 7946761 = 3171^2 + 2819^2 .

It is a Smith number, since the sum of its digits (13) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

18002002 is a modest number, since divided by 2002 gives 18 as remainder.

It is not an unprimeable number, because it can be changed into a prime (18002003) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4500499 + ... + 4500502.

Almost surely, 2^18002002 is an apocalyptic number.

18002002 is a deficient number, since it is larger than the sum of its proper divisors (9001004).

18002002 is an equidigital number, since it uses as much as digits as its factorization.

18002002 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9001003.

The product of its (nonzero) digits is 32, while the sum is 13.

The square root of 18002002 is about 4242.8766185219. The cubic root of 18002002 is about 262.0838552168.

Adding to 18002002 its reverse (20020081), we get a palindrome (38022083).

The spelling of 18002002 in words is "eighteen million, two thousand, two".