643311305436 has 24 divisors (see below), whose sum is σ = 1501080955920. Its totient is φ = 214434067072.

The previous prime is 643311305431. The next prime is 643311305447. The reversal of 643311305436 is 634503113346.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 643311305394 and 643311305403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643311305431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 606370 + ... + 1286198.

It is an arithmetic number, because the mean of its divisors is an integer number (62545039830).

Almost surely, 2^643311305436 is an apocalyptic number.

It is an amenable number.

643311305436 is an abundant number, since it is smaller than the sum of its proper divisors (857769650484).

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

643311305436 is a wasteful number, since it uses less digits than its factorization.

643311305436 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 758693 (or 758691 counting only the distinct ones).

The product of its (nonzero) digits is 233280, while the sum is 39.

The spelling of 643311305436 in words is "six hundred forty-three billion, three hundred eleven million, three hundred five thousand, four hundred thirty-six".