643064556431 has 6 divisors (see below), whose sum is σ = 706839553896. Its totient is φ = 584604142100.

The previous prime is 643064556427. The next prime is 643064556499. The reversal of 643064556431 is 134655460346.

It is not a de Polignac number, because 643064556431 - 2² = 643064556427 is a prime.

It is a super-2 number, since 2×643064556431² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643064558431) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2657291435 + ... + 2657291676.

It is an arithmetic number, because the mean of its divisors is an integer number (117806592316).

Almost surely, 2^643064556431 is an apocalyptic number.

643064556431 is a deficient number, since it is larger than the sum of its proper divisors (63774997465).

643064556431 is a wasteful number, since it uses less digits than its factorization.

643064556431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5314583133 (or 5314583122 counting only the distinct ones).

The product of its (nonzero) digits is 3110400, while the sum is 47.

The spelling of 643064556431 in words is "six hundred forty-three billion, sixty-four million, five hundred fifty-six thousand, four hundred thirty-one".