72521036640 has 672 divisors, whose sum is σ = 279259051680. Its totient is φ = 17788253184.

The previous prime is 72521036603. The next prime is 72521036657. The reversal of 72521036640 is 4663012527.

72521036640 is a `hidden beast` number, since 7 + 2 + 5 + 2 + 1 + 0 + 3 + 6 + 640 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 72521036595 and 72521036604.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 111 ways as a sum of consecutive naturals, for example, 256257939 + ... + 256258221.

It is an arithmetic number, because the mean of its divisors is an integer number (415564065).

Almost surely, 2^72521036640 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 72521036640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (139629525840).

72521036640 is an abundant number, since it is smaller than the sum of its proper divisors (206738015040).

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

72521036640 is an equidigital number, since it uses as much as digits as its factorization.

72521036640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 355 (or 306 counting only the distinct ones).

The product of its (nonzero) digits is 60480, while the sum is 36.

The spelling of 72521036640 in words is "seventy-two billion, five hundred twenty-one million, thirty-six thousand, six hundred forty".