643625643 has 8 divisors (see below), whose sum is σ = 859298256. Its totient is φ = 428518400.

The previous prime is 643625621. The next prime is 643625657. The reversal of 643625643 is 346526346.

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 643625643 - 2⁸ = 643625387 is a prime.

It is not an unprimeable number, because it can be changed into a prime (643625603) 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 7 ways as a sum of consecutive naturals, for example, 138678 + ... + 143243.

It is an arithmetic number, because the mean of its divisors is an integer number (107412282).

Almost surely, 2^643625643 is an apocalyptic number.

643625643 is a deficient number, since it is larger than the sum of its proper divisors (215672613).

643625643 is a wasteful number, since it uses less digits than its factorization.

643625643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 282685.

The product of its digits is 311040, while the sum is 39.

The square root of 643625643 is about 25369.7781425065. The cubic root of 643625643 is about 863.3981482953.

The spelling of 643625643 in words is "six hundred forty-three million, six hundred twenty-five thousand, six hundred forty-three".