221544400 has 120 divisors (see below), whose sum is σ = 663689664. Its totient is φ = 69043200.

The previous prime is 221544359. The next prime is 221544413. The reversal of 221544400 is 4445122.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 27204 + ... + 34396.

Almost surely, 2^221544400 is an apocalyptic number.

221544400 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 221544400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (331844832).

221544400 is an abundant number, since it is smaller than the sum of its proper divisors (442145264).

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

221544400 is a wasteful number, since it uses less digits than its factorization.

221544400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7229 (or 7218 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 22.

The square root of 221544400 is about 14884.3676385663. The cubic root of 221544400 is about 605.0903947076.

Adding to 221544400 its reverse (4445122), we get a palindrome (225989522).

The spelling of 221544400 in words is "two hundred twenty-one million, five hundred forty-four thousand, four hundred".