1221804 has 42 divisors (see below), whose sum is σ = 3213420. Its totient is φ = 406296.

The previous prime is 1221793. The next prime is 1221811. The reversal of 1221804 is 4081221.

1221804 is nontrivially palindromic in base 8.

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

It is an unprimeable number.

It is a polite number, since it can be written in 13 ways as a sum of consecutive naturals, for example, 2707 + ... + 3125.

It is an arithmetic number, because the mean of its divisors is an integer number (76510).

2^1221804 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1221804, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1606710).

1221804 is an abundant number, since it is smaller than the sum of its proper divisors (1991616).

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

1221804 is an equidigital number, since it uses as much as digits as its factorization.

1221804 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 441 (or 424 counting only the distinct ones).

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

The square root of 1221804 is about 1105.3524324848. The cubic root of 1221804 is about 106.9056144983.

It can be divided in two parts, 1221 and 804, that added together give a square (2025 = 45²).

The spelling of 1221804 in words is "one million, two hundred twenty-one thousand, eight hundred four".