221415221 has 4 divisors (see below), whose sum is σ = 221626944. Its totient is φ = 221203500.

The previous prime is 221415209. The next prime is 221415247. The reversal of 221415221 is 122514122.

221415221 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, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221415221 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221415193 and 221415202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221415281) 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, 104285 + ... + 106386.

It is an arithmetic number, because the mean of its divisors is an integer number (55406736).

Almost surely, 2^221415221 is an apocalyptic number.

It is an amenable number.

221415221 is a deficient number, since it is larger than the sum of its proper divisors (211723).

221415221 is a wasteful number, since it uses less digits than its factorization.

221415221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 211722.

The product of its digits is 320, while the sum is 20.

The square root of 221415221 is about 14880.0275873400. The cubic root of 221415221 is about 604.9727656616.

Adding to 221415221 its reverse (122514122), we get a palindrome (343929343).

The spelling of 221415221 in words is "two hundred twenty-one million, four hundred fifteen thousand, two hundred twenty-one".