18461813 has 4 divisors (see below), whose sum is σ = 19547820. Its totient is φ = 17375808.

The previous prime is 18461809. The next prime is 18461831. The reversal of 18461813 is 31816481.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 17247409 + 1214404 = 4153^2 + 1102^2 .

It is a cyclic number.

It is not a de Polignac number, because 18461813 - 2² = 18461809 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18461813.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18461873) 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, 542978 + ... + 543011.

It is an arithmetic number, because the mean of its divisors is an integer number (4886955).

Almost surely, 2^18461813 is an apocalyptic number.

It is an amenable number.

18461813 is a deficient number, since it is larger than the sum of its proper divisors (1086007).

18461813 is a wasteful number, since it uses less digits than its factorization.

18461813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1086006.

The product of its digits is 4608, while the sum is 32.

The square root of 18461813 is about 4296.7211917926. The cubic root of 18461813 is about 264.2965226927.

The spelling of 18461813 in words is "eighteen million, four hundred sixty-one thousand, eight hundred thirteen".