39821221 has 6 divisors (see below), whose sum is σ = 43770566. Its totient is φ = 36201000.

The previous prime is 39821203. The next prime is 39821233. The reversal of 39821221 is 12212893.

It can be written as a sum of positive squares in only one way, i.e., 22896225 + 16924996 = 4785^2 + 4114^2 .

It is not a de Polignac number, because 39821221 - 2¹¹ = 39819173 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 39821221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (39821261) 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 5 ways as a sum of consecutive naturals, for example, 164430 + ... + 164671.

Almost surely, 2^39821221 is an apocalyptic number.

It is an amenable number.

39821221 is a deficient number, since it is larger than the sum of its proper divisors (3949345).

39821221 is a wasteful number, since it uses less digits than its factorization.

39821221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 329123 (or 329112 counting only the distinct ones).

The product of its digits is 1728, while the sum is 28.

The square root of 39821221 is about 6310.4057714223. The cubic root of 39821221 is about 341.4849153767.

The spelling of 39821221 in words is "thirty-nine million, eight hundred twenty-one thousand, two hundred twenty-one".