645520915760 has 480 divisors, whose sum is σ = 1916481980160. Its totient is φ = 200879917056.

The previous prime is 645520915751. The next prime is 645520915799. The reversal of 645520915760 is 67519025546.

It is a junction number, because it is equal to n+sod(n) for n = 645520915699 and 645520915708.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 169738019 + ... + 169741821.

It is an arithmetic number, because the mean of its divisors is an integer number (3992670792).

Almost surely, 2^645520915760 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 645520915760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (958240990080).

645520915760 is an abundant number, since it is smaller than the sum of its proper divisors (1270961064400).

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

645520915760 is a wasteful number, since it uses less digits than its factorization.

645520915760 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3945 (or 3932 counting only the distinct ones).

The product of its (nonzero) digits is 2268000, while the sum is 50.

The spelling of 645520915760 in words is "six hundred forty-five billion, five hundred twenty million, nine hundred fifteen thousand, seven hundred sixty".