1821040 has 80 divisors (see below), whose sum is σ = 4874688. Its totient is φ = 626688.

The previous prime is 1821037. The next prime is 1821067. The reversal of 1821040 is 401281.

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 (16).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17629 + ... + 17731.

2^1821040 is an apocalyptic number.

1821040 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 1821040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2437344).

1821040 is an abundant number, since it is smaller than the sum of its proper divisors (3053648).

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

1821040 is a wasteful number, since it uses less digits than its factorization.

1821040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 146 (or 140 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 16.

The square root of 1821040 is about 1349.4591509194. The cubic root of 1821040 is about 122.1161663397.

The spelling of 1821040 in words is "one million, eight hundred twenty-one thousand, forty".