3975721 has 2 divisors, whose sum is σ = 3975722. Its totient is φ = 3975720.

The previous prime is 3975709. The next prime is 3975749. The reversal of 3975721 is 1275793.

3975721 is digitally balanced in base 2, 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., 3956121 + 19600 = 1989^2 + 140^2 .

It is a cyclic number.

It is not a de Polignac number, because 3975721 - 2⁷ = 3975593 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3975701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1987860 + 1987861.

It is an arithmetic number, because the mean of its divisors is an integer number (1987861).

Almost surely, 2^3975721 is an apocalyptic number.

It is an amenable number.

3975721 is a deficient number, since it is larger than the sum of its proper divisors (1).

3975721 is an equidigital number, since it uses as much as digits as its factorization.

3975721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13230, while the sum is 34.

The square root of 3975721 is about 1993.9210114746. The cubic root of 3975721 is about 158.4182822698.

The spelling of 3975721 in words is "three million, nine hundred seventy-five thousand, seven hundred twenty-one".