1720591 has 2 divisors, whose sum is σ = 1720592. Its totient is φ = 1720590.

The previous prime is 1720549. The next prime is 1720597. The reversal of 1720591 is 1950271.

It is a strong prime.

It is an emirp because it is prime and its reverse (1950271) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1720591 - 2¹⁵ = 1687823 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1720597) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 860295 + 860296.

It is an arithmetic number, because the mean of its divisors is an integer number (860296).

2^1720591 is an apocalyptic number.

1720591 is a deficient number, since it is larger than the sum of its proper divisors (1).

1720591 is an equidigital number, since it uses as much as digits as its factorization.

1720591 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 630, while the sum is 25.

The square root of 1720591 is about 1311.7130021464. The cubic root of 1720591 is about 119.8282496695.

The spelling of 1720591 in words is "one million, seven hundred twenty thousand, five hundred ninety-one".