1720505 has 8 divisors (see below), whose sum is σ = 2098824. Its totient is φ = 1353600.

The previous prime is 1720471. The next prime is 1720513. The reversal of 1720505 is 5050271.

It can be written as a sum of positive squares in 4 ways, for example, as 212521 + 1507984 = 461^2 + 1228^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1720505 - 2¹⁴ = 1704121 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2516 + ... + 3125.

It is an arithmetic number, because the mean of its divisors is an integer number (262353).

2^1720505 is an apocalyptic number.

It is an amenable number.

1720505 is a deficient number, since it is larger than the sum of its proper divisors (378319).

1720505 is an equidigital number, since it uses as much as digits as its factorization.

1720505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5707.

The product of its (nonzero) digits is 350, while the sum is 20.

The square root of 1720505 is about 1311.6802201756. The cubic root of 1720505 is about 119.8262531847.

Adding to 1720505 its reverse (5050271), we get a palindrome (6770776).

The spelling of 1720505 in words is "one million, seven hundred twenty thousand, five hundred five".