1721317 has 4 divisors (see below), whose sum is σ = 1853740. Its totient is φ = 1588896.

The previous prime is 1721299. The next prime is 1721323. The reversal of 1721317 is 7131271.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 948676 + 772641 = 974^2 + 879^2 .

It is a cyclic number.

It is not a de Polignac number, because 1721317 - 2¹⁹ = 1197029 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1721327) 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 in 3 ways as a sum of consecutive naturals, for example, 66192 + ... + 66217.

It is an arithmetic number, because the mean of its divisors is an integer number (463435).

2^1721317 is an apocalyptic number.

It is an amenable number.

1721317 is a deficient number, since it is larger than the sum of its proper divisors (132423).

1721317 is a wasteful number, since it uses less digits than its factorization.

1721317 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132422.

The product of its digits is 294, while the sum is 22.

The square root of 1721317 is about 1311.9897103255. The cubic root of 1721317 is about 119.8451010646.

Adding to 1721317 its reverse (7131271), we get a palindrome (8852588).

The spelling of 1721317 in words is "one million, seven hundred twenty-one thousand, three hundred seventeen".