645599647056 has 320 divisors, whose sum is σ = 2144702730240. Its totient is φ = 162653736960.

The previous prime is 645599646983. The next prime is 645599647057. The reversal of 645599647056 is 650746995546.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645599647057) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 86294836 + ... + 86302316.

It is an arithmetic number, because the mean of its divisors is an integer number (6702196032).

Almost surely, 2^645599647056 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 645599647056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1072351365120).

645599647056 is an abundant number, since it is smaller than the sum of its proper divisors (1499103083184).

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

645599647056 is a wasteful number, since it uses less digits than its factorization.

645599647056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8394 (or 8388 counting only the distinct ones).

The product of its (nonzero) digits is 244944000, while the sum is 66.

The spelling of 645599647056 in words is "six hundred forty-five billion, five hundred ninety-nine million, six hundred forty-seven thousand, fifty-six".