221320224 has 72 divisors (see below), whose sum is σ = 631193472. Its totient is φ = 73560960.

The previous prime is 221320223. The next prime is 221320243. The reversal of 221320224 is 422023122.

221320224 = T₂₄₁ + T₂₄₂ + ... + T₁₁₀₂.

It is a tau number, because it is divible by the number of its divisors (72).

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

It is a junction number, because it is equal to n+sod(n) for n = 221320197 and 221320206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221320223) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 123237 + ... + 125019.

It is an arithmetic number, because the mean of its divisors is an integer number (8766576).

Almost surely, 2^221320224 is an apocalyptic number.

221320224 is a gapful number since it is divisible by the number (24) 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 221320224, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (315596736).

221320224 is an abundant number, since it is smaller than the sum of its proper divisors (409873248).

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

221320224 is a wasteful number, since it uses less digits than its factorization.

221320224 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2230 (or 2219 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 18.

The square root of 221320224 is about 14876.8351473020. The cubic root of 221320224 is about 604.8862331900.

Adding to 221320224 its reverse (422023122), we get a palindrome (643343346).

The spelling of 221320224 in words is "two hundred twenty-one million, three hundred twenty thousand, two hundred twenty-four".