1099891 has 16 divisors (see below), whose sum is σ = 1284640. Its totient is φ = 933120.

The previous prime is 1099867. The next prime is 1099927. The reversal of 1099891 is 1989901.

It is a 8-Lehmer number, since φ(1099891) divides (1099891-1)⁸.

It is a cyclic number.

It is not a de Polignac number, because 1099891 - 2⁵ = 1099859 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1099891.

It is not an unprimeable number, because it can be changed into a prime (1099841) 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, 15031 + ... + 15103.

It is an arithmetic number, because the mean of its divisors is an integer number (80290).

2^1099891 is an apocalyptic number.

1099891 is the 606-th hex number.

1099891 is a deficient number, since it is larger than the sum of its proper divisors (184749).

1099891 is a wasteful number, since it uses less digits than its factorization.

1099891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 166.

The product of its (nonzero) digits is 5832, while the sum is 37.

The square root of 1099891 is about 1048.7568831717. The cubic root of 1099891 is about 103.2246017805.

It can be divided in two parts, 109 and 9891, that added together give a 4-th power (10000 = 10⁴).

The spelling of 1099891 in words is "one million, ninety-nine thousand, eight hundred ninety-one".