643678507 has 2 divisors, whose sum is σ = 643678508. Its totient is φ = 643678506.

The previous prime is 643678487. The next prime is 643678543. The reversal of 643678507 is 705876346.

643678507 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 643678507 - 2⁷ = 643678379 is a prime.

It is not a weakly prime, because it can be changed into another prime (643678597) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321839253 + 321839254.

It is an arithmetic number, because the mean of its divisors is an integer number (321839254).

Almost surely, 2^643678507 is an apocalyptic number.

643678507 is a deficient number, since it is larger than the sum of its proper divisors (1).

643678507 is an equidigital number, since it uses as much as digits as its factorization.

643678507 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 846720, while the sum is 46.

The square root of 643678507 is about 25370.8199906901. The cubic root of 643678507 is about 863.4217859645.

The spelling of 643678507 in words is "six hundred forty-three million, six hundred seventy-eight thousand, five hundred seven".