1089840 has 80 divisors (see below), whose sum is σ = 3571200. Its totient is φ = 274176.

The previous prime is 1089799. The next prime is 1089841. The reversal of 1089840 is 489801.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 1089798 and 1089807.

It is not an unprimeable number, because it can be changed into a prime (1089841) 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, 4441 + ... + 4679.

It is an arithmetic number, because the mean of its divisors is an integer number (44640).

2^1089840 is an apocalyptic number.

1089840 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 1089840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1785600).

1089840 is an abundant number, since it is smaller than the sum of its proper divisors (2481360).

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

1089840 is a wasteful number, since it uses less digits than its factorization.

1089840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 274 (or 268 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 30.

The square root of 1089840 is about 1043.9540219761. The cubic root of 1089840 is about 102.9092108513.

The spelling of 1089840 in words is "one million, eighty-nine thousand, eight hundred forty".