643534845 has 24 divisors (see below), whose sum is σ = 1086709536. Its totient is φ = 325151712.

The previous prime is 643534831. The next prime is 643534849. The reversal of 643534845 is 548435346.

It is not a de Polignac number, because 643534845 - 2¹² = 643530749 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 643534797 and 643534806.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643534849) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 54007 + ... + 64836.

It is an arithmetic number, because the mean of its divisors is an integer number (45279564).

Almost surely, 2^643534845 is an apocalyptic number.

It is an amenable number.

643534845 is a deficient number, since it is larger than the sum of its proper divisors (443174691).

643534845 is a wasteful number, since it uses less digits than its factorization.

643534845 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 118889 (or 118870 counting only the distinct ones).

The product of its digits is 691200, while the sum is 42.

The square root of 643534845 is about 25367.9885879823. The cubic root of 643534845 is about 863.3575457532.

The spelling of 643534845 in words is "six hundred forty-three million, five hundred thirty-four thousand, eight hundred forty-five".