18043613 has 12 divisors (see below), whose sum is σ = 22225212. Its totient is φ = 14555520.

The previous prime is 18043609. The next prime is 18043631. The reversal of 18043613 is 31634081.

It can be written as a sum of positive squares in 2 ways, for example, as 9966649 + 8076964 = 3157^2 + 2842^2 .

It is not a de Polignac number, because 18043613 - 2² = 18043609 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 (18043603) 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 11 ways as a sum of consecutive naturals, for example, 9998 + ... + 11663.

It is an arithmetic number, because the mean of its divisors is an integer number (1852101).

Almost surely, 2^18043613 is an apocalyptic number.

It is an amenable number.

18043613 is a deficient number, since it is larger than the sum of its proper divisors (4181599).

18043613 is a wasteful number, since it uses less digits than its factorization.

18043613 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21692 (or 21685 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 26.

The square root of 18043613 is about 4247.7774188392. Note that the first 3 decimals coincide. The cubic root of 18043613 is about 262.2856323942.

Adding to 18043613 its reverse (31634081), we get a palindrome (49677694).

The spelling of 18043613 in words is "eighteen million, forty-three thousand, six hundred thirteen".