11991866 has 4 divisors (see below), whose sum is σ = 17987802. Its totient is φ = 5995932.

The previous prime is 11991839. The next prime is 11991911. The reversal of 11991866 is 66819911.

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., 9030025 + 2961841 = 3005^2 + 1721^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2997965 + ... + 2997968.

Almost surely, 2^11991866 is an apocalyptic number.

11991866 is a deficient number, since it is larger than the sum of its proper divisors (5995936).

11991866 is an equidigital number, since it uses as much as digits as its factorization.

11991866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5995935.

The product of its digits is 23328, while the sum is 41.

The square root of 11991866 is about 3462.9273743467. The cubic root of 11991866 is about 228.8911084538.

The spelling of 11991866 in words is "eleven million, nine hundred ninety-one thousand, eight hundred sixty-six".