643625625 has 20 divisors (see below), whose sum is σ = 1072369232. Its totient is φ = 343266000.

The previous prime is 643625621. The next prime is 643625657. The reversal of 643625625 is 526526346.

It is not a de Polignac number, because 643625625 - 2² = 643625621 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643625621) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 169759 + ... + 173508.

Almost surely, 2^643625625 is an apocalyptic number.

It is an amenable number.

643625625 is a deficient number, since it is larger than the sum of its proper divisors (428743607).

643625625 is an equidigital number, since it uses as much as digits as its factorization.

643625625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 343290 (or 343275 counting only the distinct ones).

The product of its digits is 259200, while the sum is 39.

The square root of 643625625 is about 25369.7777877537. Note that the first 4 decimals coincide. The cubic root of 643625625 is about 863.3981402466.

The spelling of 643625625 in words is "six hundred forty-three million, six hundred twenty-five thousand, six hundred twenty-five".