72728305920 has 504 divisors, whose sum is σ = 267702307992. Its totient is φ = 18911232000.

The previous prime is 72728305919. The next prime is 72728305933. The reversal of 72728305920 is 2950382727.

72728305920 is a `hidden beast` number, since 7 + 2 + 7 + 28 + 30 + 592 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 3057647616 + 69670658304 = 55296^2 + 263952^2 .

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 55 ways as a sum of consecutive naturals, for example, 38256970 + ... + 38258870.

It is an arithmetic number, because the mean of its divisors is an integer number (531155373).

Almost surely, 2^72728305920 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 72728305920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (133851153996).

72728305920 is an abundant number, since it is smaller than the sum of its proper divisors (194974002072).

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

72728305920 is an equidigital number, since it uses as much as digits as its factorization.

72728305920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1981 (or 1952 counting only the distinct ones).

The product of its (nonzero) digits is 423360, while the sum is 45.

The spelling of 72728305920 in words is "seventy-two billion, seven hundred twenty-eight million, three hundred five thousand, nine hundred twenty".