1728724321 has 8 divisors (see below), whose sum is σ = 1811980800. Its totient is φ = 1646142432.

The previous prime is 1728724301. The next prime is 1728724351. The reversal of 1728724321 is 1234278271.

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 1728724321 - 2¹¹ = 1728722273 is a prime.

It is a super-2 number, since 2×1728724321² = 5976975556033822082, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1728724301) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 163396 + ... + 173653.

It is an arithmetic number, because the mean of its divisors is an integer number (226497600).

Almost surely, 2^1728724321 is an apocalyptic number.

It is an amenable number.

1728724321 is a deficient number, since it is larger than the sum of its proper divisors (83256479).

1728724321 is a wasteful number, since it uses less digits than its factorization.

1728724321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 337295.

The product of its digits is 37632, while the sum is 37.

The square root of 1728724321 is about 41577.9306964644. The cubic root of 1728724321 is about 1200.1676434768.

The spelling of 1728724321 in words is "one billion, seven hundred twenty-eight million, seven hundred twenty-four thousand, three hundred twenty-one".