3981720709 has 2 divisors, whose sum is σ = 3981720710. Its totient is φ = 3981720708.

The previous prime is 3981720643. The next prime is 3981720727. The reversal of 3981720709 is 9070271893.

It is a happy number.

3981720709 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 3891888225 + 89832484 = 62385^2 + 9478^2 .

It is an emirp because it is prime and its reverse (9070271893) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 3981720709 - 2⁷ = 3981720581 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3981750709) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1990860354 + 1990860355.

It is an arithmetic number, because the mean of its divisors is an integer number (1990860355).

Almost surely, 2^3981720709 is an apocalyptic number.

It is an amenable number.

3981720709 is a deficient number, since it is larger than the sum of its proper divisors (1).

3981720709 is an equidigital number, since it uses as much as digits as its factorization.

3981720709 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 190512, while the sum is 46.

The square root of 3981720709 is about 63100.8772442983. The cubic root of 3981720709 is about 1584.9793120925.

The spelling of 3981720709 in words is "three billion, nine hundred eighty-one million, seven hundred twenty thousand, seven hundred nine".