18012509 has 8 divisors (see below), whose sum is σ = 18711000. Its totient is φ = 17319232.

The previous prime is 18012499. The next prime is 18012541. The reversal of 18012509 is 90521081.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 1836025 + 16176484 = 1355^2 + 4022^2 .

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 18012509 - 2¹² = 18008413 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 (18012559) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6647 + ... + 8955.

It is an arithmetic number, because the mean of its divisors is an integer number (2338875).

Almost surely, 2^18012509 is an apocalyptic number.

It is an amenable number.

18012509 is a deficient number, since it is larger than the sum of its proper divisors (698491).

18012509 is a wasteful number, since it uses less digits than its factorization.

18012509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2607.

The product of its (nonzero) digits is 720, while the sum is 26.

The square root of 18012509 is about 4244.1146308741. The cubic root of 18012509 is about 262.1348343523.

The spelling of 18012509 in words is "eighteen million, twelve thousand, five hundred nine".