1221824 has 28 divisors (see below), whose sum is σ = 2569464. Its totient is φ = 574464.

The previous prime is 1221823. The next prime is 1221853. The reversal of 1221824 is 4281221.

It is a happy number.

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 1221796 and 1221805.

It is not an unprimeable number, because it can be changed into a prime (1221821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 527 + ... + 1649.

2^1221824 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 1221824, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1284732).

1221824 is an abundant number, since it is smaller than the sum of its proper divisors (1347640).

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

1221824 is a wasteful number, since it uses less digits than its factorization.

1221824 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1152 (or 1142 counting only the distinct ones).

The product of its digits is 256, while the sum is 20.

The square root of 1221824 is about 1105.3614793361. The cubic root of 1221824 is about 106.9061978162.

The spelling of 1221824 in words is "one million, two hundred twenty-one thousand, eight hundred twenty-four".