1729721 has 8 divisors (see below), whose sum is σ = 1995840. Its totient is φ = 1468368.

The previous prime is 1729711. The next prime is 1729723. The reversal of 1729721 is 1279271.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1729721 - 2¹⁰ = 1728697 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1729723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 371 + ... + 1896.

It is an arithmetic number, because the mean of its divisors is an integer number (249480).

2^1729721 is an apocalyptic number.

It is an amenable number.

1729721 is a deficient number, since it is larger than the sum of its proper divisors (266119).

1729721 is a wasteful number, since it uses less digits than its factorization.

1729721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2383.

The product of its digits is 1764, while the sum is 29.

The square root of 1729721 is about 1315.1885796341. The cubic root of 1729721 is about 120.0398247447.

The spelling of 1729721 in words is "one million, seven hundred twenty-nine thousand, seven hundred twenty-one".