645643808064 has 112 divisors (see below), whose sum is σ = 1997971924800. Its totient is φ = 203887507968.

The previous prime is 645643808057. The next prime is 645643808093. The reversal of 645643808064 is 460808346546.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a self number, because there is not a number n which added to its sum of digits gives 645643808064.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 9799707 + ... + 9865370.

Almost surely, 2^645643808064 is an apocalyptic number.

645643808064 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

645643808064 is an abundant number, since it is smaller than the sum of its proper divisors (1352328116736).

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

645643808064 is a wasteful number, since it uses less digits than its factorization.

645643808064 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19665117 (or 19665101 counting only the distinct ones).

The product of its (nonzero) digits is 13271040, while the sum is 54.

The spelling of 645643808064 in words is "six hundred forty-five billion, six hundred forty-three million, eight hundred eight thousand, sixty-four".