643614643 has 4 divisors (see below), whose sum is σ = 735559600. Its totient is φ = 551669688.

The previous prime is 643614623. The next prime is 643614707. The reversal of 643614643 is 346416346.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 643614643 - 2⁹ = 643614131 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643614623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 45972468 + ... + 45972481.

It is an arithmetic number, because the mean of its divisors is an integer number (183889900).

Almost surely, 2^643614643 is an apocalyptic number.

643614643 is a deficient number, since it is larger than the sum of its proper divisors (91944957).

643614643 is an equidigital number, since it uses as much as digits as its factorization.

643614643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91944956.

The product of its digits is 124416, while the sum is 37.

The square root of 643614643 is about 25369.5613481984. The cubic root of 643614643 is about 863.3932295801.

The spelling of 643614643 in words is "six hundred forty-three million, six hundred fourteen thousand, six hundred forty-three".