1728721445 has 8 divisors (see below), whose sum is σ = 2263053600. Its totient is φ = 1257251920.

The previous prime is 1728721433. The next prime is 1728721447. The reversal of 1728721445 is 5441278271.

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

It is not a de Polignac number, because 1728721445 - 2¹² = 1728717349 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1728721447) 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 7 ways as a sum of consecutive naturals, for example, 15715595 + ... + 15715704.

It is an arithmetic number, because the mean of its divisors is an integer number (282881700).

Almost surely, 2^1728721445 is an apocalyptic number.

It is an amenable number.

1728721445 is a deficient number, since it is larger than the sum of its proper divisors (534332155).

1728721445 is a wasteful number, since it uses less digits than its factorization.

1728721445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31431315.

The product of its digits is 125440, while the sum is 41.

The square root of 1728721445 is about 41577.8961107943. The cubic root of 1728721445 is about 1200.1669779216.

The spelling of 1728721445 in words is "one billion, seven hundred twenty-eight million, seven hundred twenty-one thousand, four hundred forty-five".