643566427 has 8 divisors (see below), whose sum is σ = 767483136. Its totient is φ = 527644392.

The previous prime is 643566421. The next prime is 643566431. The reversal of 643566427 is 724665346.

643566427 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 643566427 - 2¹¹ = 643564379 is a prime.

It is not an unprimeable number, because it can be changed into a prime (643566421) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1998493 + ... + 1998814.

It is an arithmetic number, because the mean of its divisors is an integer number (95935392).

Almost surely, 2^643566427 is an apocalyptic number.

643566427 is a deficient number, since it is larger than the sum of its proper divisors (123916709).

643566427 is a wasteful number, since it uses less digits than its factorization.

643566427 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3997337.

The product of its digits is 725760, while the sum is 43.

The square root of 643566427 is about 25368.6110577619. The cubic root of 643566427 is about 863.3716688486.

The spelling of 643566427 in words is "six hundred forty-three million, five hundred sixty-six thousand, four hundred twenty-seven".