643542 has 16 divisors (see below), whose sum is σ = 1295040. Its totient is φ = 213192.

The previous prime is 643523. The next prime is 643547. The reversal of 643542 is 245346.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643547) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1509 + ... + 1887.

It is an arithmetic number, because the mean of its divisors is an integer number (80940).

2⁶⁴³⁵⁴² is an apocalyptic number.

643542 is an abundant number, since it is smaller than the sum of its proper divisors (651498).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

643542 is a wasteful number, since it uses less digits than its factorization.

643542 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 667.

The product of its digits is 2880, while the sum is 24.

The square root of 643542 is about 802.2106955158. The cubic root of 643542 is about 86.3360745425.

Adding to 643542 its reverse (245346), we get a palindrome (888888).

The spelling of 643542 in words is "six hundred forty-three thousand, five hundred forty-two".