1821222 has 48 divisors (see below), whose sum is σ = 4372368. Its totient is φ = 544320.

The previous prime is 1821191. The next prime is 1821233. The reversal of 1821222 is 2221281.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 1821195 and 1821204.

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 23 ways as a sum of consecutive naturals, for example, 9972 + ... + 10152.

It is an arithmetic number, because the mean of its divisors is an integer number (91091).

2^1821222 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1821222, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2186184).

1821222 is an abundant number, since it is smaller than the sum of its proper divisors (2551146).

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

1821222 is a wasteful number, since it uses less digits than its factorization.

1821222 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 245 (or 242 counting only the distinct ones).

The product of its digits is 128, while the sum is 18.

The square root of 1821222 is about 1349.5265836581. The cubic root of 1821222 is about 122.1202344184.

The spelling of 1821222 in words is "one million, eight hundred twenty-one thousand, two hundred twenty-two".