643402845 has 60 divisors (see below), whose sum is σ = 1195133940. Its totient is φ = 331140096.

The previous prime is 643402831. The next prime is 643402853. The reversal of 643402845 is 548204346.

643402845 is a `hidden beast` number, since 643 + 4 + 0 + 2 + 8 + 4 + 5 = 666.

643402845 is digitally balanced in base 2 and base 6, because in such bases it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 6 ways, for example, as 1996569 + 641406276 = 1413^2 + 25326^2 .

It is not a de Polignac number, because 643402845 - 2⁷ = 643402717 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 339661 + ... + 341549.

It is an arithmetic number, because the mean of its divisors is an integer number (19918899).

Almost surely, 2^643402845 is an apocalyptic number.

It is an amenable number.

643402845 is a deficient number, since it is larger than the sum of its proper divisors (551731095).

643402845 is a wasteful number, since it uses less digits than its factorization.

643402845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1964 (or 1926 counting only the distinct ones).

The product of its (nonzero) digits is 92160, while the sum is 36.

The square root of 643402845 is about 25365.3867504519. The cubic root of 643402845 is about 863.2985119186.

The spelling of 643402845 in words is "six hundred forty-three million, four hundred two thousand, eight hundred forty-five".