18611 has 4 divisors (see below), whose sum is σ = 19152. Its totient is φ = 18072.

The previous prime is 18593. The next prime is 18617. The reversal of 18611 is 11681.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18611 is a prime.

It is a Duffinian number.

It is a plaindrome in base 15.

It is a self number, because there is not a number n which added to its sum of digits gives 18611.

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, 215 + ... + 288.

It is an arithmetic number, because the mean of its divisors is an integer number (4788).

2¹⁸⁶¹¹ is an apocalyptic number.

18611 is a deficient number, since it is larger than the sum of its proper divisors (541).

18611 is an equidigital number, since it uses as much as digits as its factorization.

18611 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 540.

The product of its digits is 48, while the sum is 17.

The square root of 18611 is about 136.4221389658. The cubic root of 18611 is about 26.5006526480.

The spelling of 18611 in words is "eighteen thousand, six hundred eleven".