11687881 has 4 divisors (see below), whose sum is σ = 11773332. Its totient is φ = 11602432.

The previous prime is 11687861. The next prime is 11687903. The reversal of 11687881 is 18878611.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18878611 = 547 ⋅34513.

It can be written as a sum of positive squares in 2 ways, for example, as 10137856 + 1550025 = 3184^2 + 1245^2 .

It is a cyclic number.

It is not a de Polignac number, because 11687881 - 2¹¹ = 11685833 is a prime.

It is a super-2 number, since 2×11687881² = 273213124540322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11687801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 42520 + ... + 42793.

It is an arithmetic number, because the mean of its divisors is an integer number (2943333).

Almost surely, 2^11687881 is an apocalyptic number.

It is an amenable number.

11687881 is a deficient number, since it is larger than the sum of its proper divisors (85451).

11687881 is an equidigital number, since it uses as much as digits as its factorization.

11687881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85450.

The product of its digits is 21504, while the sum is 40.

The square root of 11687881 is about 3418.7543052989. The cubic root of 11687881 is about 226.9404580327.

The spelling of 11687881 in words is "eleven million, six hundred eighty-seven thousand, eight hundred eighty-one".