66613 has 4 divisors (see below), whose sum is σ = 68940. Its totient is φ = 64288.

The previous prime is 66601. The next prime is 66617. The reversal of 66613 is 31666.

66613 = 182² + 183².

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

It can be written as a sum of positive squares in 2 ways, for example, as 33124 + 33489 = 182^2 + 183^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66613 is a prime.

It is a Duffinian number.

66613 is a lucky number.

It is a plaindrome in base 9.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66617) 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, 1120 + ... + 1177.

It is an arithmetic number, because the mean of its divisors is an integer number (17235).

2⁶⁶⁶¹³ is an apocalyptic number.

66613 is the 183-rd centered square number.

It is an amenable number.

66613 is a deficient number, since it is larger than the sum of its proper divisors (2327).

66613 is a wasteful number, since it uses less digits than its factorization.

66613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2326.

The product of its digits is 648, while the sum is 22.

The square root of 66613 is about 258.0949437707. The cubic root of 66613 is about 40.5371299994.

The spelling of 66613 in words is "sixty-six thousand, six hundred thirteen".