1720261 has 4 divisors (see below), whose sum is σ = 1748524. Its totient is φ = 1692000.

The previous prime is 1720231. The next prime is 1720273. The reversal of 1720261 is 1620271.

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 497025 + 1223236 = 705^2 + 1106^2 .

It is a cyclic number.

It is not a de Polignac number, because 1720261 - 2⁷ = 1720133 is a prime.

It is a Duffinian number.

1720261 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1720211) 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 in 3 ways as a sum of consecutive naturals, for example, 14040 + ... + 14161.

It is an arithmetic number, because the mean of its divisors is an integer number (437131).

2^1720261 is an apocalyptic number.

It is an amenable number.

1720261 is a deficient number, since it is larger than the sum of its proper divisors (28263).

1720261 is an equidigital number, since it uses as much as digits as its factorization.

1720261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28262.

The product of its (nonzero) digits is 168, while the sum is 19.

The square root of 1720261 is about 1311.5872064030. The cubic root of 1720261 is about 119.8205883774.

The spelling of 1720261 in words is "one million, seven hundred twenty thousand, two hundred sixty-one".