11987831 has 4 divisors (see below), whose sum is σ = 12094032. Its totient is φ = 11881632.

The previous prime is 11987783. The next prime is 11987837. The reversal of 11987831 is 13878911.

11987831 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13878911 = 19 ⋅730469.

It is a cyclic number.

It is not a de Polignac number, because 11987831 - 2¹⁴ = 11971447 is a prime.

It is a super-2 number, since 2×11987831² = 287416184169122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11987837) 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, 52931 + ... + 53156.

It is an arithmetic number, because the mean of its divisors is an integer number (3023508).

Almost surely, 2^11987831 is an apocalyptic number.

11987831 is a deficient number, since it is larger than the sum of its proper divisors (106201).

11987831 is a wasteful number, since it uses less digits than its factorization.

11987831 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106200.

The product of its digits is 12096, while the sum is 38.

The square root of 11987831 is about 3462.3447257603. The cubic root of 11987831 is about 228.8654332940.

The spelling of 11987831 in words is "eleven million, nine hundred eighty-seven thousand, eight hundred thirty-one".