91666 has 4 divisors (see below), whose sum is σ = 137502. Its totient is φ = 45832.

The previous prime is 91639. The next prime is 91673. The reversal of 91666 is 66619.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 73441 + 18225 = 271^2 + 135^2 .

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 as a sum of consecutive naturals, namely, 22915 + ... + 22918.

2⁹¹⁶⁶⁶ is an apocalyptic number.

91666 is a deficient number, since it is larger than the sum of its proper divisors (45836).

91666 is a wasteful number, since it uses less digits than its factorization.

91666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45835.

The product of its digits is 1944, while the sum is 28.

The square root of 91666 is about 302.7639344440. The cubic root of 91666 is about 45.0888778430.

It can be divided in two parts, 91 and 666, that multiplied together give a palindrome (60606).

The spelling of 91666 in words is "ninety-one thousand, six hundred sixty-six".