1728397 has 4 divisors (see below), whose sum is σ = 1885536. Its totient is φ = 1571260.

The previous prime is 1728361. The next prime is 1728403. The reversal of 1728397 is 7938271.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 7938271 = 11 ⋅721661.

It is a cyclic number.

It is not a de Polignac number, because 1728397 - 2⁷ = 1728269 is a prime.

It is a d-powerful number, because it can be written as 1 + 7 + 2¹⁷ + 8³ + 3¹³ + 9² + 7⁴ .

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1728317) 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, 78553 + ... + 78574.

It is an arithmetic number, because the mean of its divisors is an integer number (471384).

2^1728397 is an apocalyptic number.

It is an amenable number.

1728397 is a deficient number, since it is larger than the sum of its proper divisors (157139).

1728397 is a wasteful number, since it uses less digits than its factorization.

1728397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 157138.

The product of its digits is 21168, while the sum is 37.

The square root of 1728397 is about 1314.6851334065. The cubic root of 1728397 is about 120.0091891111.

The spelling of 1728397 in words is "one million, seven hundred twenty-eight thousand, three hundred ninety-seven".