728121994560 has 896 divisors, whose sum is σ = 2765145600000. Its totient is φ = 179825909760.

The previous prime is 728121994511. The next prime is 728121994603. The reversal of 728121994560 is 65499121827.

It is a happy number.

728121994560 is a `hidden beast` number, since 7 + 2 + 81 + 21 + 99 + 456 + 0 = 666.

728121994560 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a junction number, because it is equal to n+sod(n) for n = 728121994497 and 728121994506.

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, 2086309266 + ... + 2086309614.

It is an arithmetic number, because the mean of its divisors is an integer number (3086100000).

Almost surely, 2^728121994560 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 728121994560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1382572800000).

728121994560 is an abundant number, since it is smaller than the sum of its proper divisors (2037023605440).

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

728121994560 is a wasteful number, since it uses less digits than its factorization.

728121994560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 644 (or 628 counting only the distinct ones).

The product of its (nonzero) digits is 2177280, while the sum is 54.

The spelling of 728121994560 in words is "seven hundred twenty-eight billion, one hundred twenty-one million, nine hundred ninety-four thousand, five hundred sixty".