18231613 has 4 divisors (see below), whose sum is σ = 18655648. Its totient is φ = 17807580.

The previous prime is 18231601. The next prime is 18231671. The reversal of 18231613 is 31613281.

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 18231613 - 2⁵ = 18231581 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 (18231673) 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, 211953 + ... + 212038.

It is an arithmetic number, because the mean of its divisors is an integer number (4663912).

Almost surely, 2^18231613 is an apocalyptic number.

It is an amenable number.

18231613 is a deficient number, since it is larger than the sum of its proper divisors (424035).

18231613 is an equidigital number, since it uses as much as digits as its factorization.

18231613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 424034.

The product of its digits is 864, while the sum is 25.

The square root of 18231613 is about 4269.8492947644. The cubic root of 18231613 is about 263.1934222680.

Adding to 18231613 its reverse (31613281), we get a palindrome (49844894).

It can be divided in two parts, 182316 and 13, that added together give a square (182329 = 427²).

The spelling of 18231613 in words is "eighteen million, two hundred thirty-one thousand, six hundred thirteen".