728705731320 has 512 divisors, whose sum is σ = 2847591936000. Its totient is φ = 162278277120.

The previous prime is 728705731307. The next prime is 728705731343. The reversal of 728705731320 is 23137507827.

It is a happy number.

728705731320 is a `hidden beast` number, since 7 + 2 + 8 + 70 + 573 + 1 + 3 + 2 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 357382861 + ... + 357384899.

It is an arithmetic number, because the mean of its divisors is an integer number (5561703000).

Almost surely, 2^728705731320 is an apocalyptic number.

728705731320 is a gapful number since it is divisible by the number (70) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 728705731320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1423795968000).

728705731320 is an abundant number, since it is smaller than the sum of its proper divisors (2118886204680).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

728705731320 is a wasteful number, since it uses less digits than its factorization.

728705731320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3260 (or 3250 counting only the distinct ones).

The product of its (nonzero) digits is 493920, while the sum is 45.

The spelling of 728705731320 in words is "seven hundred twenty-eight billion, seven hundred five million, seven hundred thirty-one thousand, three hundred twenty".