7666 has 4 divisors (see below), whose sum is σ = 11502. Its totient is φ = 3832.

The previous prime is 7649. The next prime is 7669. The reversal of 7666 is 6667.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 6667 = 59 ⋅113.

It can be written as a sum of positive squares in only one way, i.e., 7225 + 441 = 85^2 + 21^2 .

It is a plaindrome in base 9.

It is a nialpdrome in base 10.

It is a self number, because there is not a number n which added to its sum of digits gives 7666.

It is not an unprimeable number, because it can be changed into a prime (7669) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1915 + ... + 1918.

2⁷⁶⁶⁶ is an apocalyptic number.

7666 is a deficient number, since it is larger than the sum of its proper divisors (3836).

7666 is a wasteful number, since it uses less digits than its factorization.

7666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3835.

The product of its digits is 1512, while the sum is 25.

The square root of 7666 is about 87.5556965594. Note that the first 3 decimals coincide. The cubic root of 7666 is about 19.7177007716.

Subtracting from 7666 its reverse (6667), we obtain a palindrome (999).

The spelling of 7666 in words is "seven thousand, six hundred sixty-six".