321220221 has 32 divisors (see below), whose sum is σ = 498501888. Its totient is φ = 180195840.

The previous prime is 321220217. The next prime is 321220223. The reversal of 321220221 is 122022123.

It is a happy number.

It is not a de Polignac number, because 321220221 - 2² = 321220217 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 321220221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (321220223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 485631 + ... + 486291.

It is an arithmetic number, because the mean of its divisors is an integer number (15578184).

Almost surely, 2^321220221 is an apocalyptic number.

It is an amenable number.

321220221 is a deficient number, since it is larger than the sum of its proper divisors (177281667).

321220221 is a wasteful number, since it uses less digits than its factorization.

321220221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1061.

The product of its (nonzero) digits is 96, while the sum is 15.

The square root of 321220221 is about 17922.6175822618. The cubic root of 321220221 is about 684.8586711823.

Adding to 321220221 its reverse (122022123), we get a palindrome (443242344).

The spelling of 321220221 in words is "three hundred twenty-one million, two hundred twenty thousand, two hundred twenty-one".