645683574558648 has 128 divisors (see below), whose sum is σ = 1755415122278400. Its totient is φ = 197085961119744.

The previous prime is 645683574558647. The next prime is 645683574558667. The reversal of 645683574558648 is 846855475386546.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645683574558643) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 456990261 + ... + 458400987.

It is an arithmetic number, because the mean of its divisors is an integer number (13714180642800).

Almost surely, 2^{645683574558648} is an apocalyptic number.

645683574558648 is a gapful number since it is divisible by the number (68) 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 645683574558648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (877707561139200).

645683574558648 is an abundant number, since it is smaller than the sum of its proper divisors (1109731547719752).

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

645683574558648 is a wasteful number, since it uses less digits than its factorization.

645683574558648 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1441109 (or 1441105 counting only the distinct ones).

The product of its digits is 92897280000, while the sum is 84.

The spelling of 645683574558648 in words is "six hundred forty-five trillion, six hundred eighty-three billion, five hundred seventy-four million, five hundred fifty-eight thousand, six hundred forty-eight".