221431224 has 64 divisors (see below), whose sum is σ = 634832640. Its totient is φ = 63048960.

The previous prime is 221431219. The next prime is 221431253. The reversal of 221431224 is 422134122.

221431224 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (21).

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

It is a self number, because there is not a number n which added to its sum of digits gives 221431224.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 50479 + ... + 54689.

It is an arithmetic number, because the mean of its divisors is an integer number (9919260).

Almost surely, 2^221431224 is an apocalyptic number.

221431224 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 221431224, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (317416320).

221431224 is an abundant number, since it is smaller than the sum of its proper divisors (413401416).

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

221431224 is a wasteful number, since it uses less digits than its factorization.

221431224 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4540 (or 4536 counting only the distinct ones).

The product of its digits is 768, while the sum is 21.

The square root of 221431224 is about 14880.5653118422. The cubic root of 221431224 is about 604.9873403084.

Adding to 221431224 its reverse (422134122), we get a palindrome (643565346).

The spelling of 221431224 in words is "two hundred twenty-one million, four hundred thirty-one thousand, two hundred twenty-four".