3989905921 has 2 divisors, whose sum is σ = 3989905922. Its totient is φ = 3989905920.

The previous prime is 3989905903. The next prime is 3989905943. The reversal of 3989905921 is 1295099893.

3989905921 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3699680625 + 290225296 = 60825^2 + 17036^2 .

It is a cyclic number.

It is not a de Polignac number, because 3989905921 - 2¹⁷ = 3989774849 is a prime.

It is not a weakly prime, because it can be changed into another prime (3989965921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1994952960 + 1994952961.

It is an arithmetic number, because the mean of its divisors is an integer number (1994952961).

Almost surely, 2^3989905921 is an apocalyptic number.

It is an amenable number.

3989905921 is a deficient number, since it is larger than the sum of its proper divisors (1).

3989905921 is an equidigital number, since it uses as much as digits as its factorization.

3989905921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1574640, while the sum is 55.

The square root of 3989905921 is about 63165.7020937787. The cubic root of 3989905921 is about 1586.0646478877.

The spelling of 3989905921 in words is "three billion, nine hundred eighty-nine million, nine hundred five thousand, nine hundred twenty-one".