3991717 has 2 divisors, whose sum is σ = 3991718. Its totient is φ = 3991716.

The previous prime is 3991711. The next prime is 3991723. The reversal of 3991717 is 7171993.

It is a balanced prime because it is at equal distance from previous prime (3991711) and next prime (3991723).

It can be written as a sum of positive squares in only one way, i.e., 2070721 + 1920996 = 1439^2 + 1386^2 .

It is a cyclic number.

It is not a de Polignac number, because 3991717 - 2¹⁵ = 3958949 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3991711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1995858 + 1995859.

It is an arithmetic number, because the mean of its divisors is an integer number (1995859).

Almost surely, 2^3991717 is an apocalyptic number.

It is an amenable number.

3991717 is a deficient number, since it is larger than the sum of its proper divisors (1).

3991717 is an equidigital number, since it uses as much as digits as its factorization.

3991717 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11907, while the sum is 37.

The square root of 3991717 is about 1997.9281768872. The cubic root of 3991717 is about 158.6304591211.

It can be divided in two parts, 399 and 1717, that added together give a square (2116 = 46²).

The spelling of 3991717 in words is "three million, nine hundred ninety-one thousand, seven hundred seventeen".