643665364992 has 576 divisors, whose sum is σ = 2084427072000. Its totient is φ = 190051909632.

The previous prime is 643665364967. The next prime is 643665365009. The reversal of 643665364992 is 299463566346.

643665364992 is a `hidden beast` number, since 6 + 4 + 3 + 6 + 6 + 536 + 4 + 9 + 92 = 666.

It is a tau number, because it is divible by the number of its divisors (576).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 700397109 + ... + 700398027.

It is an arithmetic number, because the mean of its divisors is an integer number (3618797000).

Almost surely, 2^643665364992 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 643665364992, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1042213536000).

643665364992 is an abundant number, since it is smaller than the sum of its proper divisors (1440761707008).

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

643665364992 is a wasteful number, since it uses less digits than its factorization.

643665364992 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1076 (or 1053 counting only the distinct ones).

The product of its digits is 151165440, while the sum is 63.

The spelling of 643665364992 in words is "six hundred forty-three billion, six hundred sixty-five million, three hundred sixty-four thousand, nine hundred ninety-two".