3971881 has 2 divisors, whose sum is σ = 3971882. Its totient is φ = 3971880.

The previous prime is 3971879. The next prime is 3971887. The reversal of 3971881 is 1881793.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3705625 + 266256 = 1925^2 + 516^2 .

It is a cyclic number.

It is not a de Polignac number, because 3971881 - 2¹ = 3971879 is a prime.

It is a super-2 number, since 2×3971881² = 31551677356322, which contains 22 as substring.

Together with 3971879, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 3971881.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3971887) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1985940 + 1985941.

It is an arithmetic number, because the mean of its divisors is an integer number (1985941).

Almost surely, 2^3971881 is an apocalyptic number.

It is an amenable number.

3971881 is a deficient number, since it is larger than the sum of its proper divisors (1).

3971881 is an equidigital number, since it uses as much as digits as its factorization.

3971881 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12096, while the sum is 37.

The square root of 3971881 is about 1992.9578520380. The cubic root of 3971881 is about 158.3672624118.

It can be divided in two parts, 397 and 1881, that added together give a triangular number (2278 = T₆₇).

The spelling of 3971881 in words is "three million, nine hundred seventy-one thousand, eight hundred eighty-one".