645691834368 has 640 divisors, whose sum is σ = 2302033789440. Its totient is φ = 176345579520.

The previous prime is 645691834363. The next prime is 645691834369. The reversal of 645691834368 is 863438196546.

645691834368 is a `hidden beast` number, since 6 + 4 + 569 + 1 + 8 + 3 + 4 + 3 + 68 = 666.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645691834363) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 427326733 + ... + 427328243.

It is an arithmetic number, because the mean of its divisors is an integer number (3596927796).

Almost surely, 2^645691834368 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 645691834368, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1151016894720).

645691834368 is an abundant number, since it is smaller than the sum of its proper divisors (1656341955072).

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

645691834368 is an equidigital number, since it uses as much as digits as its factorization.

645691834368 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1583 (or 1546 counting only the distinct ones).

The product of its digits is 89579520, while the sum is 63.

The spelling of 645691834368 in words is "six hundred forty-five billion, six hundred ninety-one million, eight hundred thirty-four thousand, three hundred sixty-eight".