221055221 has 4 divisors (see below), whose sum is σ = 222411552. Its totient is φ = 219698892.

The previous prime is 221055181. The next prime is 221055223. The reversal of 221055221 is 122550122.

It is a happy number.

221055221 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, and also an emirpimes, since its reverse is a distinct semiprime: 122550122 = 2 ⋅61275061.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221055221 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221055193 and 221055202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221055223) 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, 677921 + ... + 678246.

It is an arithmetic number, because the mean of its divisors is an integer number (55602888).

Almost surely, 2^221055221 is an apocalyptic number.

It is an amenable number.

221055221 is a deficient number, since it is larger than the sum of its proper divisors (1356331).

221055221 is a wasteful number, since it uses less digits than its factorization.

221055221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1356330.

The product of its (nonzero) digits is 400, while the sum is 20.

The square root of 221055221 is about 14867.9259145316. The cubic root of 221055221 is about 604.6447118257.

The spelling of 221055221 in words is "two hundred twenty-one million, fifty-five thousand, two hundred twenty-one".