11981139 has 4 divisors (see below), whose sum is σ = 15974856. Its totient is φ = 7987424.

The previous prime is 11981131. The next prime is 11981161. The reversal of 11981139 is 93118911.

It is a happy number.

11981139 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.

It is a cyclic number.

It is not a de Polignac number, because 11981139 - 2³ = 11981131 is a prime.

It is not an unprimeable number, because it can be changed into a prime (11981131) 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, 1996854 + ... + 1996859.

It is an arithmetic number, because the mean of its divisors is an integer number (3993714).

Almost surely, 2^11981139 is an apocalyptic number.

11981139 is a deficient number, since it is larger than the sum of its proper divisors (3993717).

11981139 is an equidigital number, since it uses as much as digits as its factorization.

11981139 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3993716.

The product of its digits is 1944, while the sum is 33.

The square root of 11981139 is about 3461.3781937257. The cubic root of 11981139 is about 228.8228386395.

The spelling of 11981139 in words is "eleven million, nine hundred eighty-one thousand, one hundred thirty-nine".