728317997 has 18 divisors (see below), whose sum is σ = 818080074. Its totient is φ = 647687040.

The previous prime is 728317987. The next prime is 728318009. The reversal of 728317997 is 799713827.

It can be written as a sum of positive squares in 3 ways, for example, as 50965321 + 677352676 = 7139^2 + 26026^2 .

It is a de Polignac number, because none of the positive numbers 2^k-728317997 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (53).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (728317907) 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 17 ways as a sum of consecutive naturals, for example, 2161013 + ... + 2161349.

It is an arithmetic number, because the mean of its divisors is an integer number (45448893).

Almost surely, 2^728317997 is an apocalyptic number.

It is an amenable number.

728317997 is a deficient number, since it is larger than the sum of its proper divisors (89762077).

728317997 is an equidigital number, since it uses as much as digits as its factorization.

728317997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 749 (or 401 counting only the distinct ones).

The product of its digits is 1333584, while the sum is 53.

The square root of 728317997 is about 26987.3673595629. The cubic root of 728317997 is about 899.7192527616.

Multiplying 728317997 by its sum of digits (53), we get a square (38600853841 = 196471²).

728317997 divided by its sum of digits (53) gives a square (13741849 = 3707²).

The spelling of 728317997 in words is "seven hundred twenty-eight million, three hundred seventeen thousand, nine hundred ninety-seven".