643529 has 4 divisors (see below), whose sum is σ = 664320. Its totient is φ = 622740.

The previous prime is 643523. The next prime is 643547. The reversal of 643529 is 925346.

643529 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 925346 = 2 ⋅462673.

It is a cyclic number.

It is not a de Polignac number, because 643529 - 2⁸ = 643273 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (643523) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10349 + ... + 10410.

It is an arithmetic number, because the mean of its divisors is an integer number (166080).

2⁶⁴³⁵²⁹ is an apocalyptic number.

It is an amenable number.

643529 is a deficient number, since it is larger than the sum of its proper divisors (20791).

643529 is a wasteful number, since it uses less digits than its factorization.

643529 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20790.

The product of its digits is 6480, while the sum is 29.

The square root of 643529 is about 802.2025928654. The cubic root of 643529 is about 86.3354931888.

The spelling of 643529 in words is "six hundred forty-three thousand, five hundred twenty-nine".