11817989 has 4 divisors (see below), whose sum is σ = 11890656. Its totient is φ = 11745324.

The previous prime is 11817983. The next prime is 11817997. The reversal of 11817989 is 98971811.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 11817989 - 2⁴ = 11817973 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11817983) 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, 36089 + ... + 36414.

It is an arithmetic number, because the mean of its divisors is an integer number (2972664).

Almost surely, 2^11817989 is an apocalyptic number.

It is an amenable number.

11817989 is a deficient number, since it is larger than the sum of its proper divisors (72667).

11817989 is an equidigital number, since it uses as much as digits as its factorization.

11817989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72666.

The product of its digits is 36288, while the sum is 44.

The square root of 11817989 is about 3437.7302104732. The cubic root of 11817989 is about 227.7794432733.

The spelling of 11817989 in words is "eleven million, eight hundred seventeen thousand, nine hundred eighty-nine".