1091840 has 36 divisors (see below), whose sum is σ = 2618364. Its totient is φ = 436224.

The previous prime is 1091837. The next prime is 1091843. The reversal of 1091840 is 481901.

It is an interprime number because it is at equal distance from previous prime (1091837) and next prime (1091843).

It can be written as a sum of positive squares in 2 ways, for example, as 200704 + 891136 = 448^2 + 944^2 .

It is a super-2 number, since 2×1091840² = 2384229171200, which contains 22 as substring.

It is a hoax number, since the sum of its digits (23) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (1091843) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 854 + ... + 1706.

2^1091840 is an apocalyptic number.

1091840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1091840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1309182).

1091840 is an abundant number, since it is smaller than the sum of its proper divisors (1526524).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1091840 is an frugal number, since it uses more digits than its factorization.

1091840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 874 (or 860 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 23.

The square root of 1091840 is about 1044.9114795044. The cubic root of 1091840 is about 102.9721230367.

The spelling of 1091840 in words is "one million, ninety-one thousand, eight hundred forty".