18231813 has 24 divisors (see below), whose sum is σ = 27495936. Its totient is φ = 11628000.

The previous prime is 18231799. The next prime is 18231821. The reversal of 18231813 is 31813281.

It is not a de Polignac number, because 18231813 - 2⁵ = 18231781 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18231853) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 27856 + ... + 28502.

It is an arithmetic number, because the mean of its divisors is an integer number (1145664).

Almost surely, 2^18231813 is an apocalyptic number.

It is an amenable number.

18231813 is a deficient number, since it is larger than the sum of its proper divisors (9264123).

18231813 is a wasteful number, since it uses less digits than its factorization.

18231813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 785 (or 782 counting only the distinct ones).

The product of its digits is 1152, while the sum is 27.

The square root of 18231813 is about 4269.8727147305. The cubic root of 18231813 is about 263.1943846712.

It can be divided in two parts, 18231 and 813, that added together give a square (19044 = 138²).

The spelling of 18231813 in words is "eighteen million, two hundred thirty-one thousand, eight hundred thirteen".