212220221 has 4 divisors (see below), whose sum is σ = 212550912. Its totient is φ = 211889532.

The previous prime is 212220191. The next prime is 212220247. The reversal of 212220221 is 122022212.

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 a cyclic number.

It is not a de Polignac number, because 212220221 - 2⁶ = 212220157 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 212220196 and 212220205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (212220121) 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, 164381 + ... + 165666.

It is an arithmetic number, because the mean of its divisors is an integer number (53137728).

Almost surely, 2^212220221 is an apocalyptic number.

It is an amenable number.

212220221 is a deficient number, since it is larger than the sum of its proper divisors (330691).

212220221 is an equidigital number, since it uses as much as digits as its factorization.

212220221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 330690.

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 212220221 is about 14567.7802358492. The cubic root of 212220221 is about 596.4795895443.

Adding to 212220221 its reverse (122022212), we get a palindrome (334242433).

The spelling of 212220221 in words is "two hundred twelve million, two hundred twenty thousand, two hundred twenty-one".