820000221 has 8 divisors (see below), whose sum is σ = 1093466400. Its totient is φ = 546600432.

The previous prime is 820000177. The next prime is 820000261. The reversal of 820000221 is 122000028.

820000221 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 820000221 - 2¹⁴ = 819983837 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 820000221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (820000261) 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, 36426 + ... + 54468.

It is an arithmetic number, because the mean of its divisors is an integer number (136683300).

Almost surely, 2^820000221 is an apocalyptic number.

It is an amenable number.

820000221 is a deficient number, since it is larger than the sum of its proper divisors (273466179).

820000221 is a wasteful number, since it uses less digits than its factorization.

820000221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33195.

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

The square root of 820000221 is about 28635.6459853798. The cubic root of 820000221 is about 935.9902464010.

Adding to 820000221 its reverse (122000028), we get a palindrome (942000249).

The spelling of 820000221 in words is "eight hundred twenty million, two hundred twenty-one", and thus it is an aban number.