221322400 has 108 divisors (see below), whose sum is σ = 585419562. Its totient is φ = 81669120.

The previous prime is 221322397. The next prime is 221322401. The reversal of 221322400 is 4223122.

It can be written as a sum of positive squares in 9 ways, for example, as 41011216 + 180311184 = 6404^2 + 13428^2 .

It is a Harshad number since it is a multiple of its sum of digits (16).

It is not an unprimeable number, because it can be changed into a prime (221322401) by changing a digit.

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 17 ways as a sum of consecutive naturals, for example, 134382 + ... + 136018.

Almost surely, 2^221322400 is an apocalyptic number.

221322400 is a gapful number since it is divisible by the number (20) 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 221322400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (292709781).

221322400 is an abundant number, since it is smaller than the sum of its proper divisors (364097162).

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

221322400 is a wasteful number, since it uses less digits than its factorization.

221322400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1683 (or 1657 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 16.

The square root of 221322400 is about 14876.9082809568. The cubic root of 221322400 is about 604.8882155787. Note that the first 3 decimals are identical.

Adding to 221322400 its reverse (4223122), we get a palindrome (225545522).

The spelling of 221322400 in words is "two hundred twenty-one million, three hundred twenty-two thousand, four hundred".