18018009 has 6 divisors (see below), whose sum is σ = 26026026. Its totient is φ = 12012000.

The previous prime is 18017981. The next prime is 18018017. The reversal of 18018009 is 90081081.

It can be written as a sum of positive squares in only one way, i.e., 9018009 + 9000000 = 3003^2 + 3000^2 .

It is not a de Polignac number, because 18018009 - 2¹² = 18013913 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18018029) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1000992 + ... + 1001009.

It is an arithmetic number, because the mean of its divisors is an integer number (4337671).

Almost surely, 2^18018009 is an apocalyptic number.

It is an amenable number.

18018009 is a deficient number, since it is larger than the sum of its proper divisors (8008017).

18018009 is a wasteful number, since it uses less digits than its factorization.

18018009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2002007 (or 2002004 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 27.

The square root of 18018009 is about 4244.7625375279. The cubic root of 18018009 is about 262.1615120141.

It can be divided in two parts, 1 and 8018009, that added together give a triangular number (8018010 = T₄₀₀₄).

The spelling of 18018009 in words is "eighteen million, eighteen thousand, nine".