1118991 has 16 divisors (see below), whose sum is σ = 1625184. Its totient is φ = 681984.

The previous prime is 1118987. The next prime is 1118993. The reversal of 1118991 is 1998111.

It is a happy number.

It is not a de Polignac number, because 1118991 - 2² = 1118987 is a prime.

1118991 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1118993) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1591 + ... + 2183.

It is an arithmetic number, because the mean of its divisors is an integer number (101574).

2^1118991 is an apocalyptic number.

1118991 is a deficient number, since it is larger than the sum of its proper divisors (506193).

1118991 is a wasteful number, since it uses less digits than its factorization.

1118991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 650.

The product of its digits is 648, while the sum is 30.

The square root of 1118991 is about 1057.8237093202. The cubic root of 1118991 is about 103.8186867950.

It can be divided in two parts, 111 and 8991, that multiplied together give a square (998001 = 999²).

The spelling of 1118991 in words is "one million, one hundred eighteen thousand, nine hundred ninety-one".