18009001 has 8 divisors (see below), whose sum is σ = 19128744. Its totient is φ = 16896000.

The previous prime is 18008993. The next prime is 18009031. The reversal of 18009001 is 10090081.

18009001 is a nontrivial binomial coefficient, being equal to C(6002, 2).

It can be written as a sum of positive squares in 4 ways, for example, as 4326400 + 13682601 = 2080^2 + 3699^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 18009001 - 2³ = 18008993 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18009001.

It is not an unprimeable number, because it can be changed into a prime (18009031) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4501 + ... + 7501.

It is an arithmetic number, because the mean of its divisors is an integer number (2391093).

Almost surely, 2^18009001 is an apocalyptic number.

18009001 is the 6001-st triangular number and also the 3001-st hexagonal number.

18009001 is the 2001-st centered nonagonal number.

It is an amenable number.

18009001 is a deficient number, since it is larger than the sum of its proper divisors (1119743).

18009001 is a wasteful number, since it uses less digits than its factorization.

18009001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3371.

The product of its (nonzero) digits is 72, while the sum is 19.

The square root of 18009001 is about 4243.7013325634. The cubic root of 18009001 is about 262.1178160179.

Adding to 18009001 its reverse (10090081), we get a palindrome (28099082).

It can be divided in two parts, 1800 and 9001, that added together give a palindrome (10801).

The spelling of 18009001 in words is "eighteen million, nine thousand, one".