643391431672 has 64 divisors (see below), whose sum is σ = 1358947814400. Its totient is φ = 282919392000.

The previous prime is 643391431643. The next prime is 643391431691. The reversal of 643391431672 is 276134193346.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8196772 + ... + 8274892.

It is an arithmetic number, because the mean of its divisors is an integer number (21233559600).

Almost surely, 2^643391431672 is an apocalyptic number.

643391431672 is a gapful number since it is divisible by the number (62) 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 643391431672, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (679473907200).

643391431672 is an abundant number, since it is smaller than the sum of its proper divisors (715556382728).

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

643391431672 is a wasteful number, since it uses less digits than its factorization.

643391431672 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81188 (or 81184 counting only the distinct ones).

The product of its digits is 1959552, while the sum is 49.

The spelling of 643391431672 in words is "six hundred forty-three billion, three hundred ninety-one million, four hundred thirty-one thousand, six hundred seventy-two".