221304421 has 4 divisors (see below), whose sum is σ = 238327852. Its totient is φ = 204280992.

The previous prime is 221304403. The next prime is 221304439. The reversal of 221304421 is 124403122.

221304421 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 is an interprime number because it is at equal distance from previous prime (221304403) and next prime (221304439).

It can be written as a sum of positive squares in 2 ways, for example, as 95550625 + 125753796 = 9775^2 + 11214^2 .

It is a cyclic number.

It is not a de Polignac number, because 221304421 - 2⁵ = 221304389 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221304451) 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, 8511696 + ... + 8511721.

It is an arithmetic number, because the mean of its divisors is an integer number (59581963).

Almost surely, 2^221304421 is an apocalyptic number.

It is an amenable number.

221304421 is a deficient number, since it is larger than the sum of its proper divisors (17023431).

221304421 is a wasteful number, since it uses less digits than its factorization.

221304421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17023430.

The product of its (nonzero) digits is 384, while the sum is 19.

The square root of 221304421 is about 14876.3040100692. The cubic root of 221304421 is about 604.8718358845.

Adding to 221304421 its reverse (124403122), we get a palindrome (345707543).

The spelling of 221304421 in words is "two hundred twenty-one million, three hundred four thousand, four hundred twenty-one".