3971309 has 2 divisors, whose sum is σ = 3971310. Its totient is φ = 3971308.

The previous prime is 3971299. The next prime is 3971311. The reversal of 3971309 is 9031793.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2815684 + 1155625 = 1678^2 + 1075^2 .

It is an emirp because it is prime and its reverse (9031793) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 3971309 - 2⁸ = 3971053 is a prime.

Together with 3971311, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3971809) 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 as a sum of consecutive naturals, namely, 1985654 + 1985655.

It is an arithmetic number, because the mean of its divisors is an integer number (1985655).

Almost surely, 2^3971309 is an apocalyptic number.

It is an amenable number.

3971309 is a deficient number, since it is larger than the sum of its proper divisors (1).

3971309 is an equidigital number, since it uses as much as digits as its factorization.

3971309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5103, while the sum is 32.

The square root of 3971309 is about 1992.8143415783. The cubic root of 3971309 is about 158.3596597652.

The spelling of 3971309 in words is "three million, nine hundred seventy-one thousand, three hundred nine".