1165891 has 4 divisors (see below), whose sum is σ = 1182384. Its totient is φ = 1149400.

The previous prime is 1165889. The next prime is 1165903. The reversal of 1165891 is 1985611.

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 1165891 - 2¹ = 1165889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1165831) 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, 8140 + ... + 8281.

It is an arithmetic number, because the mean of its divisors is an integer number (295596).

2^1165891 is an apocalyptic number.

1165891 is a deficient number, since it is larger than the sum of its proper divisors (16493).

1165891 is an equidigital number, since it uses as much as digits as its factorization.

1165891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16492.

The product of its digits is 2160, while the sum is 31.

The square root of 1165891 is about 1079.7643261379. The cubic root of 1165891 is about 105.2493243619.

The spelling of 1165891 in words is "one million, one hundred sixty-five thousand, eight hundred ninety-one".