721764128072 has 128 divisors (see below), whose sum is σ = 1658920435200. Its totient is φ = 290704785408.

The previous prime is 721764128051. The next prime is 721764128077. The reversal of 721764128072 is 270821467127.

It is a Harshad number since it is a multiple of its sum of digits (47).

It is not an unprimeable number, because it can be changed into a prime (721764128077) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1350248 + ... + 1807400.

It is an arithmetic number, because the mean of its divisors is an integer number (12960315900).

Almost surely, 2^721764128072 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 721764128072, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (829460217600).

721764128072 is an abundant number, since it is smaller than the sum of its proper divisors (937156307128).

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

721764128072 is a wasteful number, since it uses less digits than its factorization.

721764128072 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 457255 (or 457251 counting only the distinct ones).

The product of its (nonzero) digits is 526848, while the sum is 47.

The spelling of 721764128072 in words is "seven hundred twenty-one billion, seven hundred sixty-four million, one hundred twenty-eight thousand, seventy-two".