643436 has 12 divisors (see below), whose sum is σ = 1162560. Its totient is φ = 311280.

The previous prime is 643429. The next prime is 643439. The reversal of 643436 is 634346.

643436 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not an unprimeable number, because it can be changed into a prime (643439) 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, 2471 + ... + 2718.

It is an arithmetic number, because the mean of its divisors is an integer number (96880).

2⁶⁴³⁴³⁶ is an apocalyptic number.

It is an amenable number.

643436 is a deficient number, since it is larger than the sum of its proper divisors (519124).

643436 is a wasteful number, since it uses less digits than its factorization.

643436 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5224 (or 5222 counting only the distinct ones).

The product of its digits is 5184, while the sum is 26.

The square root of 643436 is about 802.1446253638. The cubic root of 643436 is about 86.3313340457.

The spelling of 643436 in words is "six hundred forty-three thousand, four hundred thirty-six".