7256521728 has 220 divisors, whose sum is σ = 21935160720. Its totient is φ = 2389229568.

The previous prime is 7256521721. The next prime is 7256521739. The reversal of 7256521728 is 8271256527.

7256521728 is a `hidden beast` number, since 7 + 2 + 56 + 521 + 72 + 8 = 666.

It is a super-2 number, since 2×7256521728² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7256521721) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 7381525 + ... + 7382507.

It is an arithmetic number, because the mean of its divisors is an integer number (99705276).

Almost surely, 2^7256521728 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 7256521728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (10967580360).

7256521728 is an abundant number, since it is smaller than the sum of its proper divisors (14678638992).

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

7256521728 is an equidigital number, since it uses as much as digits as its factorization.

7256521728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1104 (or 1077 counting only the distinct ones).

The product of its digits is 470400, while the sum is 45.

The square root of 7256521728 is about 85185.2201264985. The cubic root of 7256521728 is about 1936.0184867210.

The spelling of 7256521728 in words is "seven billion, two hundred fifty-six million, five hundred twenty-one thousand, seven hundred twenty-eight".