221101221 has 16 divisors (see below), whose sum is σ = 324790848. Its totient is φ = 132672000.

The previous prime is 221101219. The next prime is 221101247. The reversal of 221101221 is 122101122.

It is not a de Polignac number, because 221101221 - 2¹ = 221101219 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 221101197 and 221101206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221101211) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 29836 + ... + 36501.

It is an arithmetic number, because the mean of its divisors is an integer number (20299428).

Almost surely, 2^221101221 is an apocalyptic number.

It is an amenable number.

221101221 is a deficient number, since it is larger than the sum of its proper divisors (103689627).

221101221 is a wasteful number, since it uses less digits than its factorization.

221101221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66452.

The product of its (nonzero) digits is 16, while the sum is 12.

The square root of 221101221 is about 14869.4727882329. The cubic root of 221101221 is about 604.6866496539.

Adding to 221101221 its reverse (122101122), we get a palindrome (343202343).

Subtracting from 221101221 its reverse (122101122), we obtain a palindrome (99000099).

The spelling of 221101221 in words is "two hundred twenty-one million, one hundred one thousand, two hundred twenty-one".