11991663 has 12 divisors (see below), whose sum is σ = 17789928. Its totient is φ = 7778160.

The previous prime is 11991659. The next prime is 11991689. The reversal of 11991663 is 36619911.

It is not a de Polignac number, because 11991663 - 2² = 11991659 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11991643) 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 11 ways as a sum of consecutive naturals, for example, 17673 + ... + 18338.

It is an arithmetic number, because the mean of its divisors is an integer number (1482494).

Almost surely, 2^11991663 is an apocalyptic number.

11991663 is a deficient number, since it is larger than the sum of its proper divisors (5798265).

11991663 is a wasteful number, since it uses less digits than its factorization.

11991663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36054 (or 36051 counting only the distinct ones).

The product of its digits is 8748, while the sum is 36.

The square root of 11991663 is about 3462.8980637610. The cubic root of 11991663 is about 228.8898168795.

The spelling of 11991663 in words is "eleven million, nine hundred ninety-one thousand, six hundred sixty-three".