11987999 has 4 divisors (see below), whose sum is σ = 12012336. Its totient is φ = 11963664.

The previous prime is 11987981. The next prime is 11988029. The reversal of 11987999 is 99978911.

11987999 is nontrivially palindromic in base 7.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 99978911 = 257 ⋅389023.

It is a cyclic number.

It is not a de Polignac number, because 11987999 - 2⁸ = 11987743 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 11987999.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11987909) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11414 + ... + 12419.

It is an arithmetic number, because the mean of its divisors is an integer number (3003084).

Almost surely, 2^11987999 is an apocalyptic number.

11987999 is a deficient number, since it is larger than the sum of its proper divisors (24337).

11987999 is an equidigital number, since it uses as much as digits as its factorization.

11987999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24336.

The product of its digits is 367416, while the sum is 53.

The square root of 11987999 is about 3462.3689866910. The cubic root of 11987999 is about 228.8665024118.

The spelling of 11987999 in words is "eleven million, nine hundred eighty-seven thousand, nine hundred ninety-nine".