18475813 has 4 divisors (see below), whose sum is σ = 19112940. Its totient is φ = 17838688.

The previous prime is 18475801. The next prime is 18475817. The reversal of 18475813 is 31857481.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 31857481 = 37 ⋅861013.

It can be written as a sum of positive squares in 2 ways, for example, as 14915044 + 3560769 = 3862^2 + 1887^2 .

It is a cyclic number.

It is not a de Polignac number, because 18475813 - 2⁵ = 18475781 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 (18475817) 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 3 ways as a sum of consecutive naturals, for example, 318520 + ... + 318577.

It is an arithmetic number, because the mean of its divisors is an integer number (4778235).

Almost surely, 2^18475813 is an apocalyptic number.

It is an amenable number.

18475813 is a deficient number, since it is larger than the sum of its proper divisors (637127).

18475813 is an equidigital number, since it uses as much as digits as its factorization.

18475813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 637126.

The product of its digits is 26880, while the sum is 37.

The square root of 18475813 is about 4298.3500322798. The cubic root of 18475813 is about 264.3633131068.

The spelling of 18475813 in words is "eighteen million, four hundred seventy-five thousand, eight hundred thirteen".