645518396322 has 54 divisors (see below), whose sum is σ = 1476257355963. Its totient is φ = 203827462344.

The previous prime is 645518396233. The next prime is 645518396323. The reversal of 645518396322 is 223693815546.

It is a happy number.

645518396322 is a `hidden beast` number, since 6 + 4 + 5 + 518 + 3 + 96 + 32 + 2 = 666.

It can be written as a sum of positive squares in only one way, i.e., 322759198161 + 322759198161 = 568119^2 + 568119^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=568119.

It is not an unprimeable number, because it can be changed into a prime (645518396323) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 64760583 + ... + 64770549.

Almost surely, 2^645518396322 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 645518396322

645518396322 is an abundant number, since it is smaller than the sum of its proper divisors (830738959641).

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

645518396322 is an frugal number, since it uses more digits than its factorization.

645518396322 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19980 (or 9991 counting only the distinct ones).

The product of its digits is 9331200, while the sum is 54.

The spelling of 645518396322 in words is "six hundred forty-five billion, five hundred eighteen million, three hundred ninety-six thousand, three hundred twenty-two".