66845 has 8 divisors (see below), whose sum is σ = 83160. Its totient is φ = 51520.

The previous prime is 66841. The next prime is 66851. The reversal of 66845 is 54866.

66845 = T₁₆ + T₁₇ + ... + T₇₃.

It can be written as a sum of positive squares in 4 ways, for example, as 3844 + 63001 = 62^2 + 251^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 66845 - 2² = 66841 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (29).

It is a Curzon 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 (66841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 86 + ... + 375.

It is an arithmetic number, because the mean of its divisors is an integer number (10395).

2⁶⁶⁸⁴⁵ is an apocalyptic number.

It is an amenable number.

66845 is a deficient number, since it is larger than the sum of its proper divisors (16315).

66845 is a wasteful number, since it uses less digits than its factorization.

66845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 495.

The product of its digits is 5760, while the sum is 29.

The square root of 66845 is about 258.5440001238. The cubic root of 66845 is about 40.5841364250.

The spelling of 66845 in words is "sixty-six thousand, eight hundred forty-five".