66823 has 4 divisors (see below), whose sum is σ = 70360. Its totient is φ = 63288.

The previous prime is 66821. The next prime is 66841. The reversal of 66823 is 32866.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 32866 = 2 ⋅16433.

It is a cyclic number.

It is not a de Polignac number, because 66823 - 2¹ = 66821 is a prime.

It is the 259-th Hogben number.

It is a Duffinian number.

66823 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66821) by changing a digit.

It is a nontrivial repunit in base 258.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1740 + ... + 1777.

It is an arithmetic number, because the mean of its divisors is an integer number (17590).

2⁶⁶⁸²³ is an apocalyptic number.

66823 is a deficient number, since it is larger than the sum of its proper divisors (3537).

66823 is a wasteful number, since it uses less digits than its factorization.

66823 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3536.

The product of its digits is 1728, while the sum is 25.

The square root of 66823 is about 258.5014506729. The cubic root of 66823 is about 40.5796835915.

The spelling of 66823 in words is "sixty-six thousand, eight hundred twenty-three".