3936637981 has 2 divisors, whose sum is σ = 3936637982. Its totient is φ = 3936637980.

The previous prime is 3936637909. The next prime is 3936638021. The reversal of 3936637981 is 1897366393.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 3935052900 + 1585081 = 62730^2 + 1259^2 .

It is a cyclic number.

It is not a de Polignac number, because 3936637981 - 2⁹ = 3936637469 is a prime.

It is a super-2 number, since 2×3936637981² = 30994237186903512722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3936637781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1968318990 + 1968318991.

It is an arithmetic number, because the mean of its divisors is an integer number (1968318991).

Almost surely, 2^3936637981 is an apocalyptic number.

It is an amenable number.

3936637981 is a deficient number, since it is larger than the sum of its proper divisors (1).

3936637981 is an equidigital number, since it uses as much as digits as its factorization.

3936637981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4408992, while the sum is 55.

The square root of 3936637981 is about 62742.6328822755. The cubic root of 3936637981 is about 1578.9746566761.

The spelling of 3936637981 in words is "three billion, nine hundred thirty-six million, six hundred thirty-seven thousand, nine hundred eighty-one".