7866 has 24 divisors (see below), whose sum is σ = 18720. Its totient is φ = 2376.

The previous prime is 7853. The next prime is 7867. The reversal of 7866 is 6687.

It is a Curzon number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 7866.

It is not an unprimeable number, because it can be changed into a prime (7867) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 331 + ... + 353.

It is an arithmetic number, because the mean of its divisors is an integer number (780).

2⁷⁸⁶⁶ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 7866, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (9360).

7866 is an abundant number, since it is smaller than the sum of its proper divisors (10854).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

7866 is a wasteful number, since it uses less digits than its factorization.

7866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50 (or 47 counting only the distinct ones).

The product of its digits is 2016, while the sum is 27.

The square root of 7866 is about 88.6904729946. The cubic root of 7866 is about 19.8877039938.

It can be divided in two parts, 78 and 66, that added together give a square (144 = 12²).

The spelling of 7866 in words is "seven thousand, eight hundred sixty-six".