643503971880 has 1920 divisors, whose sum is σ = 2948278798080. Its totient is φ = 124157214720.

The previous prime is 643503971867. The next prime is 643503971909. The reversal of 643503971880 is 88179305346.

643503971880 is a `hidden beast` number, since 6 + 43 + 503 + 9 + 7 + 18 + 80 = 666.

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

It is an unprimeable number.

It is a polite number, since it can be written in 479 ways as a sum of consecutive naturals, for example, 1486152144 + ... + 1486152576.

It is an arithmetic number, because the mean of its divisors is an integer number (1535561874).

Almost surely, 2^643503971880 is an apocalyptic number.

643503971880 is a gapful number since it is divisible by the number (60) 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 643503971880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1474139399040).

643503971880 is an abundant number, since it is smaller than the sum of its proper divisors (2304774826200).

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

643503971880 is a wasteful number, since it uses less digits than its factorization.

643503971880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 541 (or 521 counting only the distinct ones).

The product of its (nonzero) digits is 4354560, while the sum is 54.

The spelling of 643503971880 in words is "six hundred forty-three billion, five hundred three million, nine hundred seventy-one thousand, eight hundred eighty".