18522509 has 4 divisors (see below), whose sum is σ = 18776316. Its totient is φ = 18268704.

The previous prime is 18522487. The next prime is 18522527. The reversal of 18522509 is 90522581.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90522581 = 337 ⋅268613.

It can be written as a sum of positive squares in 2 ways, for example, as 13912900 + 4609609 = 3730^2 + 2147^2 .

It is a cyclic number.

It is not a de Polignac number, because 18522509 - 2¹² = 18518413 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 (18522709) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 126794 + ... + 126939.

It is an arithmetic number, because the mean of its divisors is an integer number (4694079).

Almost surely, 2^18522509 is an apocalyptic number.

It is an amenable number.

18522509 is a deficient number, since it is larger than the sum of its proper divisors (253807).

18522509 is an equidigital number, since it uses as much as digits as its factorization.

18522509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 253806.

The product of its (nonzero) digits is 7200, while the sum is 32.

The square root of 18522509 is about 4303.7784561940. The cubic root of 18522509 is about 264.5858441134.

The spelling of 18522509 in words is "eighteen million, five hundred twenty-two thousand, five hundred nine".