645847835396544 has 1344 divisors, whose sum is σ = 2218757253672960. Its totient is φ = 184430297088000.

The previous prime is 645847835396479. The next prime is 645847835396579. The reversal of 645847835396544 is 445693538748546.

It is a happy number.

645847835396544 is a `hidden beast` number, since 6 + 4 + 5 + 8 + 4 + 7 + 8 + 35 + 39 + 6 + 544 = 666.

It is a Harshad number since it is a multiple of its sum of digits (81).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 128937477112 + ... + 128937482120.

It is an arithmetic number, because the mean of its divisors is an integer number (1650861051840).

Almost surely, 2^{645847835396544} is an apocalyptic number.

645847835396544 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 645847835396544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1109378626836480).

645847835396544 is an abundant number, since it is smaller than the sum of its proper divisors (1572909418276416).

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

645847835396544 is a wasteful number, since it uses less digits than its factorization.

645847835396544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5712 (or 5690 counting only the distinct ones).

The product of its digits is 41803776000, while the sum is 81.

The spelling of 645847835396544 in words is "six hundred forty-five trillion, eight hundred forty-seven billion, eight hundred thirty-five million, three hundred ninety-six thousand, five hundred forty-four".