1189991 has 8 divisors (see below), whose sum is σ = 1306368. Its totient is φ = 1075000.

The previous prime is 1189967. The next prime is 1189999. The reversal of 1189991 is 1999811.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1189991 - 2¹⁸ = 927847 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 (1189999) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2546 + ... + 2976.

It is an arithmetic number, because the mean of its divisors is an integer number (163296).

2^1189991 is an apocalyptic number.

1189991 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1189991 is a deficient number, since it is larger than the sum of its proper divisors (116377).

1189991 is a wasteful number, since it uses less digits than its factorization.

1189991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 693.

The product of its digits is 5832, while the sum is 38.

The square root of 1189991 is about 1090.8670863125. The cubic root of 1189991 is about 105.9695830609.

The spelling of 1189991 in words is "one million, one hundred eighty-nine thousand, nine hundred ninety-one".