643624425 has 18 divisors (see below), whose sum is σ = 1152803262. Its totient is φ = 343266240.

The previous prime is 643624381. The next prime is 643624427. The reversal of 643624425 is 524426346.

643624425 is a `hidden beast` number, since 6 + 4 + 3 + 624 + 4 + 25 = 666.

It can be written as a sum of positive squares in 3 ways, for example, as 8433216 + 635191209 = 2904^2 + 25203^2 .

It is not a de Polignac number, because 643624425 - 2¹⁹ = 643100137 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 643624425.

It is not an unprimeable number, because it can be changed into a prime (643624427) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 1430052 + ... + 1430501.

Almost surely, 2^643624425 is an apocalyptic number.

It is an amenable number.

643624425 is a deficient number, since it is larger than the sum of its proper divisors (509178837).

643624425 is a wasteful number, since it uses less digits than its factorization.

643624425 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2860569 (or 2860561 counting only the distinct ones).

The product of its digits is 138240, while the sum is 36.

The square root of 643624425 is about 25369.7541375552. The cubic root of 643624425 is about 863.3976036622.

The spelling of 643624425 in words is "six hundred forty-three million, six hundred twenty-four thousand, four hundred twenty-five".