643242539520 has 720 divisors, whose sum is σ = 2644248043008. Its totient is φ = 146999992320.

The previous prime is 643242539503. The next prime is 643242539521. The reversal of 643242539520 is 25935242346.

643242539520 is a `hidden beast` number, since 6 + 4 + 32 + 42 + 53 + 9 + 520 = 666.

It is a tau number, because it is divible by the number of its divisors (720).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (643242539521) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 117570385 + ... + 117575855.

Almost surely, 2^643242539520 is an apocalyptic number.

643242539520 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 643242539520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1322124021504).

643242539520 is an abundant number, since it is smaller than the sum of its proper divisors (2001005503488).

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

643242539520 is an frugal number, since it uses more digits than its factorization.

643242539520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5525 (or 5488 counting only the distinct ones).

The product of its (nonzero) digits is 1555200, while the sum is 45.

The spelling of 643242539520 in words is "six hundred forty-three billion, two hundred forty-two million, five hundred thirty-nine thousand, five hundred twenty".