3817721 has 2 divisors, whose sum is σ = 3817722. Its totient is φ = 3817720.

The previous prime is 3817717. The next prime is 3817739. The reversal of 3817721 is 1277183.

3817721 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., 2062096 + 1755625 = 1436^2 + 1325^2 .

It is a cyclic number.

It is not a de Polignac number, because 3817721 - 2² = 3817717 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3817621) 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, 1908860 + 1908861.

It is an arithmetic number, because the mean of its divisors is an integer number (1908861).

Almost surely, 2^3817721 is an apocalyptic number.

It is an amenable number.

3817721 is a deficient number, since it is larger than the sum of its proper divisors (1).

3817721 is an equidigital number, since it uses as much as digits as its factorization.

3817721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2352, while the sum is 29.

The square root of 3817721 is about 1953.8989226672. The cubic root of 3817721 is about 156.2912731501.

The spelling of 3817721 in words is "three million, eight hundred seventeen thousand, seven hundred twenty-one".