221430221 has 4 divisors (see below), whose sum is σ = 221568444. Its totient is φ = 221292000.

The previous prime is 221430203. The next prime is 221430227. The reversal of 221430221 is 122034122.

221430221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 119137225 + 102292996 = 10915^2 + 10114^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221430221 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 221430221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221430227) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66680 + ... + 69921.

It is an arithmetic number, because the mean of its divisors is an integer number (55392111).

Almost surely, 2^221430221 is an apocalyptic number.

It is an amenable number.

221430221 is a deficient number, since it is larger than the sum of its proper divisors (138223).

221430221 is a wasteful number, since it uses less digits than its factorization.

221430221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 138222.

The product of its (nonzero) digits is 192, while the sum is 17.

The square root of 221430221 is about 14880.5316101274. The cubic root of 221430221 is about 604.9864268521.

Adding to 221430221 its reverse (122034122), we get a palindrome (343464343).

The spelling of 221430221 in words is "two hundred twenty-one million, four hundred thirty thousand, two hundred twenty-one".