18730813 has 4 divisors (see below), whose sum is σ = 18773920. Its totient is φ = 18687708.

The previous prime is 18730807. The next prime is 18730823. The reversal of 18730813 is 31803781.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 18730813 - 2⁹ = 18730301 is a prime.

It is a super-3 number, since 3×18730813³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18730823) 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, 20895 + ... + 21772.

It is an arithmetic number, because the mean of its divisors is an integer number (4693480).

Almost surely, 2^18730813 is an apocalyptic number.

It is an amenable number.

18730813 is a deficient number, since it is larger than the sum of its proper divisors (43107).

18730813 is an equidigital number, since it uses as much as digits as its factorization.

18730813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43106.

The product of its (nonzero) digits is 4032, while the sum is 31.

The square root of 18730813 is about 4327.9109279189. The cubic root of 18730813 is about 265.5739925679.

The spelling of 18730813 in words is "eighteen million, seven hundred thirty thousand, eight hundred thirteen".