20613 has 4 divisors (see below), whose sum is σ = 27488.
Its totient is φ = 13740.
The previous prime is 20611. The next prime is 20627. The reversal of 20613 is 31602.
20613 is nontrivially palindromic in base 2 and base 8.
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 not a de Polignac number, because 20613 - 21 = 20611 is a prime.
It is a D-number.
It is a Duffinian number.
It is a Curzon number.
20613 is a lucky number.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (20611) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (5) of ones.
It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3433 + ... + 3438.
It is an arithmetic number, because the mean of its divisors is an integer number (6872).
220613 is an apocalyptic number.
It is an amenable number.
20613 is a deficient number, since it is larger than the sum of its proper divisors (6875).
20613 is an equidigital number, since it uses as much as digits as its factorization.
20613 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 6874.
The product of its (nonzero) digits is 36, while the sum is 12.
The square root of 20613 is about 143.5722814474.
The cubic root of 20613 is about 27.4187131301.
The spelling of 20613 in words is "twenty thousand, six hundred thirteen".