1728220 has 72 divisors (see below), whose sum is σ = 4332384. Its totient is φ = 574464.

The previous prime is 1728193. The next prime is 1728229. The reversal of 1728220 is 228271.

It is a junction number, because it is equal to n+sod(n) for n = 1728191 and 1728200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1728229) 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 23 ways as a sum of consecutive naturals, for example, 75129 + ... + 75151.

It is an arithmetic number, because the mean of its divisors is an integer number (60172).

2^1728220 is an apocalyptic number.

1728220 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 1728220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2166192).

1728220 is an abundant number, since it is smaller than the sum of its proper divisors (2604164).

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

1728220 is a wasteful number, since it uses less digits than its factorization.

1728220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79 (or 60 counting only the distinct ones).

The product of its (nonzero) digits is 448, while the sum is 22.

The square root of 1728220 is about 1314.6178151843. The cubic root of 1728220 is about 120.0050923765.

The spelling of 1728220 in words is "one million, seven hundred twenty-eight thousand, two hundred twenty".