3971439421 has 2 divisors, whose sum is σ = 3971439422. Its totient is φ = 3971439420.

The previous prime is 3971439403. The next prime is 3971439467. The reversal of 3971439421 is 1249341793.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3409275321 + 562164100 = 58389^2 + 23710^2 .

It is a cyclic number.

It is not a de Polignac number, because 3971439421 - 2²³ = 3963050813 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3971439491) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1985719710 + 1985719711.

It is an arithmetic number, because the mean of its divisors is an integer number (1985719711).

Almost surely, 2^3971439421 is an apocalyptic number.

It is an amenable number.

3971439421 is a deficient number, since it is larger than the sum of its proper divisors (1).

3971439421 is an equidigital number, since it uses as much as digits as its factorization.

3971439421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 163296, while the sum is 43.

The square root of 3971439421 is about 63019.3575102127. The cubic root of 3971439421 is about 1583.6139329935.

The spelling of 3971439421 in words is "three billion, nine hundred seventy-one million, four hundred thirty-nine thousand, four hundred twenty-one".