643605825 has 12 divisors (see below), whose sum is σ = 1064095088. Its totient is φ = 343256400.

The previous prime is 643605817. The next prime is 643605847. The reversal of 643605825 is 528506346.

It is not a de Polignac number, because 643605825 - 2³ = 643605817 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4290631 + ... + 4290780.

Almost surely, 2^643605825 is an apocalyptic number.

It is an amenable number.

643605825 is a deficient number, since it is larger than the sum of its proper divisors (420489263).

643605825 is a wasteful number, since it uses less digits than its factorization.

643605825 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8581424 (or 8581419 counting only the distinct ones).

The product of its (nonzero) digits is 172800, while the sum is 39.

The square root of 643605825 is about 25369.3875566597. The cubic root of 643605825 is about 863.3892865186.

The spelling of 643605825 in words is "six hundred forty-three million, six hundred five thousand, eight hundred twenty-five".