212221221 has 8 divisors (see below), whose sum is σ = 283382304. Its totient is φ = 141270480.

The previous prime is 212221181. The next prime is 212221223. The reversal of 212221221 is 122122212.

212221221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 212221221 - 2⁶ = 212221157 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 212221221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (212221223) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 50215 + ... + 54276.

It is an arithmetic number, because the mean of its divisors is an integer number (35422788).

Almost surely, 2^212221221 is an apocalyptic number.

It is an amenable number.

212221221 is a deficient number, since it is larger than the sum of its proper divisors (71161083).

212221221 is a wasteful number, since it uses less digits than its factorization.

212221221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105171.

The product of its digits is 64, while the sum is 15.

The square root of 212221221 is about 14567.8145581278. The cubic root of 212221221 is about 596.4805264306.

Adding to 212221221 its reverse (122122212), we get a palindrome (334343433).

Subtracting from 212221221 its reverse (122122212), we obtain a palindrome (90099009).

The spelling of 212221221 in words is "two hundred twelve million, two hundred twenty-one thousand, two hundred twenty-one".