1720105 has 4 divisors (see below), whose sum is σ = 2064132. Its totient is φ = 1376080.

The previous prime is 1720063. The next prime is 1720109. The reversal of 1720105 is 5010271.

1720105 is nontrivially palindromic in base 4.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5010271 = 7 ⋅715753.

It can be written as a sum of positive squares in 2 ways, for example, as 1315609 + 404496 = 1147^2 + 636^2 .

It is a de Polignac number, because none of the positive numbers 2^k-1720105 is a prime.

It is a super-2 number, since 2×1720105² = 5917522422050, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1720109) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 172006 + ... + 172015.

It is an arithmetic number, because the mean of its divisors is an integer number (516033).

2^1720105 is an apocalyptic number.

It is an amenable number.

1720105 is a deficient number, since it is larger than the sum of its proper divisors (344027).

1720105 is an equidigital number, since it uses as much as digits as its factorization.

1720105 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 344026.

The product of its (nonzero) digits is 70, while the sum is 16.

The square root of 1720105 is about 1311.5277351242. The cubic root of 1720105 is about 119.8169663346.

Adding to 1720105 its reverse (5010271), we get a palindrome (6730376).

The spelling of 1720105 in words is "one million, seven hundred twenty thousand, one hundred five".