221222400 has 240 divisors, whose sum is σ = 836208384. Its totient is φ = 50503680.

The previous prime is 221222389. The next prime is 221222413. The reversal of 221222400 is 4222122.

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 221222400.

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, 268389 + ... + 269211.

Almost surely, 2^221222400 is an apocalyptic number.

221222400 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 221222400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (418104192).

221222400 is an abundant number, since it is smaller than the sum of its proper divisors (614985984).

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

221222400 is an equidigital number, since it uses as much as digits as its factorization.

221222400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 861 (or 840 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 15.

The square root of 221222400 is about 14873.5469878573. The cubic root of 221222400 is about 604.7970997313.

Adding to 221222400 its reverse (4222122), we get a palindrome (225444522).

The spelling of 221222400 in words is "two hundred twenty-one million, two hundred twenty-two thousand, four hundred".