66813 has 4 divisors (see below), whose sum is σ = 89088. Its totient is φ = 44540.

The previous prime is 66809. The next prime is 66821. The reversal of 66813 is 31866.

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 66813 - 2² = 66809 is a prime.

It is a D-number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66853) 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, 11133 + ... + 11138.

It is an arithmetic number, because the mean of its divisors is an integer number (22272).

2⁶⁶⁸¹³ is an apocalyptic number.

It is an amenable number.

66813 is a deficient number, since it is larger than the sum of its proper divisors (22275).

66813 is a wasteful number, since it uses less digits than its factorization.

66813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22274.

The product of its digits is 864, while the sum is 24.

The square root of 66813 is about 258.4821076980. The cubic root of 66813 is about 40.5776592532.

The spelling of 66813 in words is "sixty-six thousand, eight hundred thirteen".