66685 has 4 divisors (see below), whose sum is σ = 80028. Its totient is φ = 53344.

The previous prime is 66683. The next prime is 66697. The reversal of 66685 is 58666.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 58666 = 2 ⋅29333.

It can be written as a sum of positive squares in 2 ways, for example, as 21316 + 45369 = 146^2 + 213^2 .

It is a cyclic number.

It is not a de Polignac number, because 66685 - 2¹ = 66683 is a prime.

It is a magnanimous number.

It is a Duffinian number.

It is a plaindrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66683) 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, 6664 + ... + 6673.

It is an arithmetic number, because the mean of its divisors is an integer number (20007).

2⁶⁶⁶⁸⁵ is an apocalyptic number.

It is an amenable number.

66685 is a deficient number, since it is larger than the sum of its proper divisors (13343).

66685 is a wasteful number, since it uses less digits than its factorization.

66685 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13342.

The product of its digits is 8640, while the sum is 31.

The square root of 66685 is about 258.2343896541. The cubic root of 66685 is about 40.5517298644.

The spelling of 66685 in words is "sixty-six thousand, six hundred eighty-five".