643564523 has 8 divisors (see below), whose sum is σ = 774213120. Its totient is φ = 522593640.

The previous prime is 643564513. The next prime is 643564553. The reversal of 643564523 is 325465346.

It is a happy number.

643564523 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 643564523 - 2¹⁶ = 643498987 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643564513) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2419283 + ... + 2419548.

It is an arithmetic number, because the mean of its divisors is an integer number (96776640).

Almost surely, 2^643564523 is an apocalyptic number.

643564523 is a deficient number, since it is larger than the sum of its proper divisors (130648597).

643564523 is a wasteful number, since it uses less digits than its factorization.

643564523 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4838857.

The product of its digits is 259200, while the sum is 38.

The square root of 643564523 is about 25368.5735310443. The cubic root of 643564523 is about 863.3708174155.

The spelling of 643564523 in words is "six hundred forty-three million, five hundred sixty-four thousand, five hundred twenty-three".