221020221 has 4 divisors (see below), whose sum is σ = 294693632. Its totient is φ = 147346812.

The previous prime is 221020211. The next prime is 221020237. The reversal of 221020221 is 122020122.

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 not a de Polignac number, because 221020221 - 2⁶ = 221020157 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221020197 and 221020206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221020211) 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, 36836701 + ... + 36836706.

It is an arithmetic number, because the mean of its divisors is an integer number (73673408).

Almost surely, 2^221020221 is an apocalyptic number.

It is an amenable number.

221020221 is a deficient number, since it is larger than the sum of its proper divisors (73673411).

221020221 is an equidigital number, since it uses as much as digits as its factorization.

221020221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73673410.

The product of its (nonzero) digits is 32, while the sum is 12.

The square root of 221020221 is about 14866.7488375906. The cubic root of 221020221 is about 604.6127987109.

Adding to 221020221 its reverse (122020122), we get a palindrome (343040343).

Subtracting from 221020221 its reverse (122020122), we obtain a palindrome (99000099).

The spelling of 221020221 in words is "two hundred twenty-one million, twenty thousand, two hundred twenty-one".