82218221 has 8 divisors (see below), whose sum is σ = 83963064. Its totient is φ = 80490240.

The previous prime is 82218217. The next prime is 82218247. The reversal of 82218221 is 12281228.

It can be written as a sum of positive squares in 4 ways, for example, as 37515625 + 44702596 = 6125^2 + 6686^2 .

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

It is not a de Polignac number, because 82218221 - 2² = 82218217 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (82218251) 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, 5891 + ... + 14111.

It is an arithmetic number, because the mean of its divisors is an integer number (10495383).

Almost surely, 2^82218221 is an apocalyptic number.

It is an amenable number.

82218221 is a deficient number, since it is larger than the sum of its proper divisors (1744843).

82218221 is a wasteful number, since it uses less digits than its factorization.

82218221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8431.

The product of its digits is 1024, while the sum is 26.

The square root of 82218221 is about 9067.4263713581. The cubic root of 82218221 is about 434.8331962743.

Adding to 82218221 its reverse (12281228), we get a palindrome (94499449).

The spelling of 82218221 in words is "eighty-two million, two hundred eighteen thousand, two hundred twenty-one".