1720280 has 32 divisors (see below), whose sum is σ = 4006800. Its totient is φ = 663936.

The previous prime is 1720273. The next prime is 1720289. The reversal of 1720280 is 820271.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a nialpdrome in base 11.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1720289) 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 7 ways as a sum of consecutive naturals, for example, 419 + ... + 1901.

2^1720280 is an apocalyptic number.

1720280 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1720280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2003400).

1720280 is an abundant number, since it is smaller than the sum of its proper divisors (2286520).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1720280 is a wasteful number, since it uses less digits than its factorization.

1720280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1523 (or 1519 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 20.

The square root of 1720280 is about 1311.5944495156. The cubic root of 1720280 is about 119.8210295087.

Subtracting from 1720280 its reverse (820271), we obtain a palindrome (900009).

The spelling of 1720280 in words is "one million, seven hundred twenty thousand, two hundred eighty".