3903985721 has 2 divisors, whose sum is σ = 3903985722. Its totient is φ = 3903985720.

The previous prime is 3903985711. The next prime is 3903985741. The reversal of 3903985721 is 1275893093.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3876307600 + 27678121 = 62260^2 + 5261^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-3903985721 is a prime.

It is a super-2 number, since 2×3903985721² = 30482209019543779682, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (3903985711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1951992860 + 1951992861.

It is an arithmetic number, because the mean of its divisors is an integer number (1951992861).

Almost surely, 2^3903985721 is an apocalyptic number.

It is an amenable number.

3903985721 is a deficient number, since it is larger than the sum of its proper divisors (1).

3903985721 is an equidigital number, since it uses as much as digits as its factorization.

3903985721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 408240, while the sum is 47.

The square root of 3903985721 is about 62481.8831422357. The cubic root of 3903985721 is about 1574.5969535239.

The spelling of 3903985721 in words is "three billion, nine hundred three million, nine hundred eighty-five thousand, seven hundred twenty-one".