11663999 has 4 divisors (see below), whose sum is σ = 11672664. Its totient is φ = 11655336.

The previous prime is 11663983. The next prime is 11664017. The reversal of 11663999 is 99936611.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 99936611 = 4159 ⋅24029.

It is a cyclic number.

It is not a de Polignac number, because 11663999 - 2⁴ = 11663983 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11663909) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1832 + ... + 5165.

It is an arithmetic number, because the mean of its divisors is an integer number (2918166).

Almost surely, 2^11663999 is an apocalyptic number.

11663999 is a deficient number, since it is larger than the sum of its proper divisors (8665).

11663999 is an equidigital number, since it uses as much as digits as its factorization.

11663999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8664.

The product of its digits is 78732, while the sum is 44.

The square root of 11663999 is about 3415.2597265801. The cubic root of 11663999 is about 226.7857825000.

The spelling of 11663999 in words is "eleven million, six hundred sixty-three thousand, nine hundred ninety-nine".