1720211 has 2 divisors, whose sum is σ = 1720212. Its totient is φ = 1720210.

The previous prime is 1720189. The next prime is 1720217. The reversal of 1720211 is 1120271.

It is a strong prime.

It is an emirp because it is prime and its reverse (1120271) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1720211 - 2¹⁰ = 1719187 is a prime.

It is not a weakly prime, because it can be changed into another prime (1720217) 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, 860105 + 860106.

It is an arithmetic number, because the mean of its divisors is an integer number (860106).

2^1720211 is an apocalyptic number.

1720211 is a deficient number, since it is larger than the sum of its proper divisors (1).

1720211 is an equidigital number, since it uses as much as digits as its factorization.

1720211 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 28, while the sum is 14.

The square root of 1720211 is about 1311.5681453893. The cubic root of 1720211 is about 119.8194274901.

Adding to 1720211 its reverse (1120271), we get a palindrome (2840482).

The spelling of 1720211 in words is "one million, seven hundred twenty thousand, two hundred eleven".