643672643 has 2 divisors, whose sum is σ = 643672644. Its totient is φ = 643672642.

The previous prime is 643672637. The next prime is 643672663. The reversal of 643672643 is 346276346.

643672643 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 643672643 - 2¹⁴ = 643656259 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 643672643.

It is not a weakly prime, because it can be changed into another prime (643672613) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321836321 + 321836322.

It is an arithmetic number, because the mean of its divisors is an integer number (321836322).

Almost surely, 2^643672643 is an apocalyptic number.

643672643 is a deficient number, since it is larger than the sum of its proper divisors (1).

643672643 is an equidigital number, since it uses as much as digits as its factorization.

643672643 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 435456, while the sum is 41.

The square root of 643672643 is about 25370.7044245918. The cubic root of 643672643 is about 863.4191639927.

The spelling of 643672643 in words is "six hundred forty-three million, six hundred seventy-two thousand, six hundred forty-three".