66985 has 4 divisors (see below), whose sum is σ = 80388. Its totient is φ = 53584.

The previous prime is 66977. The next prime is 67003. The reversal of 66985 is 58966.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 58966 = 2 ⋅29483.

It can be written as a sum of positive squares in 2 ways, for example, as 10816 + 56169 = 104^2 + 237^2 .

It is a cyclic number.

It is not a de Polignac number, because 66985 - 2³ = 66977 is a prime.

It is a Duffinian number.

66985 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 66985.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 6694 + ... + 6703.

It is an arithmetic number, because the mean of its divisors is an integer number (20097).

2⁶⁶⁹⁸⁵ is an apocalyptic number.

It is an amenable number.

66985 is a deficient number, since it is larger than the sum of its proper divisors (13403).

66985 is a wasteful number, since it uses less digits than its factorization.

66985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13402.

The product of its digits is 12960, while the sum is 34.

The square root of 66985 is about 258.8146054611. The cubic root of 66985 is about 40.6124497722.

It can be divided in two parts, 669 and 85, that multiplied together give a palindrome (56865).

The spelling of 66985 in words is "sixty-six thousand, nine hundred eighty-five".