221204421 has 6 divisors (see below), whose sum is σ = 319517510. Its totient is φ = 147469608.

The previous prime is 221204413. The next prime is 221204429. The reversal of 221204421 is 124402122.

221204421 is a `hidden beast` number, since 221 + 2 + 0 + 442 + 1 = 666.

It is an interprime number because it is at equal distance from previous prime (221204413) and next prime (221204429).

It can be written as a sum of positive squares in only one way, i.e., 220968225 + 236196 = 14865^2 + 486^2 .

It is not a de Polignac number, because 221204421 - 2³ = 221204413 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221204394 and 221204403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221204429) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 12289126 + ... + 12289143.

Almost surely, 2^221204421 is an apocalyptic number.

It is an amenable number.

221204421 is a deficient number, since it is larger than the sum of its proper divisors (98313089).

221204421 is a wasteful number, since it uses less digits than its factorization.

221204421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24578275 (or 24578272 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

The square root of 221204421 is about 14872.9425804042. The cubic root of 221204421 is about 604.7807151012.

Adding to 221204421 its reverse (124402122), we get a palindrome (345606543).

The spelling of 221204421 in words is "two hundred twenty-one million, two hundred four thousand, four hundred twenty-one".