18106813 has 4 divisors (see below), whose sum is σ = 18403708. Its totient is φ = 17809920.

The previous prime is 18106787. The next prime is 18106831. The reversal of 18106813 is 31860181.

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 7628644 + 10478169 = 2762^2 + 3237^2 .

It is a cyclic number.

It is not a de Polignac number, because 18106813 - 2⁹ = 18106301 is a prime.

It is a Duffinian number.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18106843) 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, 148356 + ... + 148477.

It is an arithmetic number, because the mean of its divisors is an integer number (4600927).

Almost surely, 2^18106813 is an apocalyptic number.

It is an amenable number.

18106813 is a deficient number, since it is larger than the sum of its proper divisors (296895).

18106813 is an equidigital number, since it uses as much as digits as its factorization.

18106813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 296894.

The product of its (nonzero) digits is 1152, while the sum is 28.

The square root of 18106813 is about 4255.2101005708. The cubic root of 18106813 is about 262.5915049089.

Adding to 18106813 its reverse (31860181), we get a palindrome (49966994).

The spelling of 18106813 in words is "eighteen million, one hundred six thousand, eight hundred thirteen".