643996713 has 16 divisors (see below), whose sum is σ = 866617920. Its totient is φ = 425371584.

The previous prime is 643996709. The next prime is 643996721. The reversal of 643996713 is 317699346.

It is not a de Polignac number, because 643996713 - 2² = 643996709 is a prime.

It is not an unprimeable number, because it can be changed into a prime (643996723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 155295 + ... + 159387.

It is an arithmetic number, because the mean of its divisors is an integer number (54163620).

Almost surely, 2^643996713 is an apocalyptic number.

It is an amenable number.

643996713 is a deficient number, since it is larger than the sum of its proper divisors (222621207).

643996713 is a wasteful number, since it uses less digits than its factorization.

643996713 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4568.

The product of its digits is 734832, while the sum is 48.

The square root of 643996713 is about 25377.0903178438. The cubic root of 643996713 is about 863.5640416238.

The spelling of 643996713 in words is "six hundred forty-three million, nine hundred ninety-six thousand, seven hundred thirteen".