18613 has 4 divisors (see below), whose sum is σ = 21280. Its totient is φ = 15948.

The previous prime is 18593. The next prime is 18617. The reversal of 18613 is 31681.

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, and also an emirpimes, since its reverse is a distinct semiprime: 31681 = 13 ⋅2437.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18613 is a prime.

It is a plaindrome in base 15.

It is a nialpdrome in base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18617) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1323 + ... + 1336.

It is an arithmetic number, because the mean of its divisors is an integer number (5320).

2¹⁸⁶¹³ is an apocalyptic number.

It is an amenable number.

18613 is a deficient number, since it is larger than the sum of its proper divisors (2667).

18613 is an equidigital number, since it uses as much as digits as its factorization.

18613 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2666.

The product of its digits is 144, while the sum is 19.

The square root of 18613 is about 136.4294689574. The cubic root of 18613 is about 26.5016018968.

The spelling of 18613 in words is "eighteen thousand, six hundred thirteen".