9866 has 4 divisors (see below), whose sum is σ = 14802. Its totient is φ = 4932.

The previous prime is 9859. The next prime is 9871. The reversal of 9866 is 6689.

9866 is an esthetic number in base 8, because in such base its adjacent digits differ by 1.

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., 9025 + 841 = 95^2 + 29^2 .

It is a plaindrome in base 16.

It is a nialpdrome in base 10.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2465 + ... + 2468.

2⁹⁸⁶⁶ is an apocalyptic number.

9866 is a deficient number, since it is larger than the sum of its proper divisors (4936).

9866 is a wasteful number, since it uses less digits than its factorization.

9866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4935.

The product of its digits is 2592, while the sum is 29.

The square root of 9866 is about 99.3277403347. The cubic root of 9866 is about 21.4476824218.

The spelling of 9866 in words is "nine thousand, eight hundred sixty-six".