821221206 has 32 divisors (see below), whose sum is σ = 1787035488. Its totient is φ = 250076160.

The previous prime is 821221171. The next prime is 821221301. The reversal of 821221206 is 602122128.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 46705 + ... + 61836.

It is an arithmetic number, because the mean of its divisors is an integer number (55844859).

Almost surely, 2^821221206 is an apocalyptic number.

821221206 is an abundant number, since it is smaller than the sum of its proper divisors (965814282).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

821221206 is a wasteful number, since it uses less digits than its factorization.

821221206 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 108656.

The product of its (nonzero) digits is 768, while the sum is 24.

The square root of 821221206 is about 28656.9573751297. The cubic root of 821221206 is about 936.4545809478.

The spelling of 821221206 in words is "eight hundred twenty-one million, two hundred twenty-one thousand, two hundred six".