1728681 has 4 divisors (see below), whose sum is σ = 2304912. Its totient is φ = 1152452.

The previous prime is 1728659. The next prime is 1728689. The reversal of 1728681 is 1868271.

It is a happy number.

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.

It is a cyclic number.

It is not a de Polignac number, because 1728681 - 2¹⁵ = 1695913 is a prime.

It is a super-2 number, since 2×1728681² = 5976675999522, which contains 22 as substring.

It is a D-number.

It is not an unprimeable number, because it can be changed into a prime (1728689) 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, 288111 + ... + 288116.

It is an arithmetic number, because the mean of its divisors is an integer number (576228).

2^1728681 is an apocalyptic number.

It is an amenable number.

1728681 is a deficient number, since it is larger than the sum of its proper divisors (576231).

1728681 is an equidigital number, since it uses as much as digits as its factorization.

1728681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 576230.

The product of its digits is 5376, while the sum is 33.

The square root of 1728681 is about 1314.7931396231. The cubic root of 1728681 is about 120.0157618185.

The spelling of 1728681 in words is "one million, seven hundred twenty-eight thousand, six hundred eighty-one".