643514464240 has 40 divisors (see below), whose sum is σ = 1501044708240. Its totient is φ = 256567320576.

The previous prime is 643514464237. The next prime is 643514464247. The reversal of 643514464240 is 42464415346.

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×643514464240² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643514464247) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 13076305 + ... + 13125424.

It is an arithmetic number, because the mean of its divisors is an integer number (37526117706).

Almost surely, 2^643514464240 is an apocalyptic number.

It is an amenable number.

643514464240 is an abundant number, since it is smaller than the sum of its proper divisors (857530244000).

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

643514464240 is a wasteful number, since it uses less digits than its factorization.

643514464240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26202049 (or 26202043 counting only the distinct ones).

The product of its (nonzero) digits is 1105920, while the sum is 43.

Adding to 643514464240 its reverse (42464415346), we get a palindrome (685978879586).

The spelling of 643514464240 in words is "six hundred forty-three billion, five hundred fourteen million, four hundred sixty-four thousand, two hundred forty".