639543 has 4 divisors (see below), whose sum is σ = 852728. Its totient is φ = 426360.

The previous prime is 639533. The next prime is 639547. The reversal of 639543 is 345936.

It is a happy number.

639543 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.

It is not a de Polignac number, because 639543 - 2⁵ = 639511 is a prime.

It is a D-number.

It is a Duffinian number.

It is a nialpdrome in base 15.

It is a self number, because there is not a number n which added to its sum of digits gives 639543.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639547) 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, 106588 + ... + 106593.

It is an arithmetic number, because the mean of its divisors is an integer number (213182).

2⁶³⁹⁵⁴³ is an apocalyptic number.

639543 is a deficient number, since it is larger than the sum of its proper divisors (213185).

639543 is a wasteful number, since it uses less digits than its factorization.

639543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 213184.

The product of its digits is 9720, while the sum is 30.

The square root of 639543 is about 799.7143239933. The cubic root of 639543 is about 86.1568707034.

The spelling of 639543 in words is "six hundred thirty-nine thousand, five hundred forty-three".