39971221 has 4 divisors (see below), whose sum is σ = 39984172. Its totient is φ = 39958272.

The previous prime is 39971219. The next prime is 39971227. The reversal of 39971221 is 12217993.

It is a happy number.

39971221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 20124196 + 19847025 = 4486^2 + 4455^2 .

It is a cyclic number.

It is not a de Polignac number, because 39971221 - 2¹ = 39971219 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (39971227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1141 + ... + 9013.

It is an arithmetic number, because the mean of its divisors is an integer number (9996043).

Almost surely, 2^39971221 is an apocalyptic number.

It is an amenable number.

39971221 is a deficient number, since it is larger than the sum of its proper divisors (12951).

39971221 is an equidigital number, since it uses as much as digits as its factorization.

39971221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12950.

The product of its digits is 6804, while the sum is 34.

The square root of 39971221 is about 6322.2797312362. The cubic root of 39971221 is about 341.9131506610.

The spelling of 39971221 in words is "thirty-nine million, nine hundred seventy-one thousand, two hundred twenty-one".