645326506656 has 192 divisors, whose sum is σ = 2030392224000. Its totient is φ = 198228446208.

The previous prime is 645326506637. The next prime is 645326506667. The reversal of 645326506656 is 656605623546.

645326506656 is a `hidden beast` number, since 6 + 4 + 53 + 26 + 506 + 65 + 6 = 666.

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

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6680010 + ... + 6775926.

It is an arithmetic number, because the mean of its divisors is an integer number (10574959500).

Almost surely, 2^645326506656 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 645326506656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1015196112000).

645326506656 is an abundant number, since it is smaller than the sum of its proper divisors (1385065717344).

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

645326506656 is a wasteful number, since it uses less digits than its factorization.

645326506656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 96548 (or 96534 counting only the distinct ones).

The product of its (nonzero) digits is 23328000, while the sum is 54.

The spelling of 645326506656 in words is "six hundred forty-five billion, three hundred twenty-six million, five hundred six thousand, six hundred fifty-six".