11187891 has 24 divisors (see below), whose sum is σ = 18987696. Its totient is φ = 6258240.

The previous prime is 11187877. The next prime is 11187899. The reversal of 11187891 is 19878111.

It is a happy number.

It is not a de Polignac number, because 11187891 - 2⁵ = 11187859 is a prime.

It is not an unprimeable number, because it can be changed into a prime (11187899) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3060 + ... + 5633.

It is an arithmetic number, because the mean of its divisors is an integer number (791154).

Almost surely, 2^11187891 is an apocalyptic number.

11187891 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

11187891 is a deficient number, since it is larger than the sum of its proper divisors (7799805).

11187891 is a wasteful number, since it uses less digits than its factorization.

11187891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8723 (or 8720 counting only the distinct ones).

The product of its digits is 4032, while the sum is 36.

The square root of 11187891 is about 3344.8304889785. The cubic root of 11187891 is about 223.6571271710.

It can be divided in two parts, 1118 and 7891, that added together give a palindrome (9009).

The spelling of 11187891 in words is "eleven million, one hundred eighty-seven thousand, eight hundred ninety-one".