18385513 has 4 divisors (see below), whose sum is σ = 18394180. Its totient is φ = 18376848.

The previous prime is 18385481. The next prime is 18385519. The reversal of 18385513 is 31558381.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 10478169 + 7907344 = 3237^2 + 2812^2 .

It is a cyclic number.

It is not a de Polignac number, because 18385513 - 2⁵ = 18385481 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18385519) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1231 + ... + 6187.

It is an arithmetic number, because the mean of its divisors is an integer number (4598545).

Almost surely, 2^18385513 is an apocalyptic number.

It is an amenable number.

18385513 is a deficient number, since it is larger than the sum of its proper divisors (8667).

18385513 is an equidigital number, since it uses as much as digits as its factorization.

18385513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8666.

The product of its digits is 14400, while the sum is 34.

The square root of 18385513 is about 4287.8331357458. The cubic root of 18385513 is about 263.9319201939.

The spelling of 18385513 in words is "eighteen million, three hundred eighty-five thousand, five hundred thirteen".