643878865975680 has 192 divisors, whose sum is σ = 2226183929096400. Its totient is φ = 171485595537408.

The previous prime is 643878865975669. The next prime is 643878865975691. The reversal of 643878865975680 is 86579568878346.

643878865975680 is a `hidden beast` number, since 6 + 4 + 3 + 8 + 7 + 8 + 8 + 6 + 597 + 5 + 6 + 8 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (643878865975669) and next prime (643878865975691).

It is a tau number, because it is divible by the number of its divisors (192).

It is a Harshad number since it is a multiple of its sum of digits (90).

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 23 ways as a sum of consecutive naturals, for example, 65537590 + ... + 74719029.

Almost surely, 2^{643878865975680} is an apocalyptic number.

643878865975680 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

643878865975680 is an abundant number, since it is smaller than the sum of its proper divisors (1582305063120720).

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

643878865975680 is a wasteful number, since it uses less digits than its factorization.

643878865975680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 140257441 (or 140257426 counting only the distinct ones).

The product of its (nonzero) digits is 117050572800, while the sum is 90.

The spelling of 643878865975680 in words is "six hundred forty-three trillion, eight hundred seventy-eight billion, eight hundred sixty-five million, nine hundred seventy-five thousand, six hundred eighty".