643343539 has 4 divisors (see below), whose sum is σ = 644623056. Its totient is φ = 642064024.

The previous prime is 643343513. The next prime is 643343543. The reversal of 643343539 is 935343346.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 643343539 - 2⁵ = 643343507 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643343579) 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, 639004 + ... + 640009.

It is an arithmetic number, because the mean of its divisors is an integer number (161155764).

Almost surely, 2^643343539 is an apocalyptic number.

643343539 is a deficient number, since it is larger than the sum of its proper divisors (1279517).

643343539 is a wasteful number, since it uses less digits than its factorization.

643343539 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1279516.

The product of its digits is 349920, while the sum is 40.

The square root of 643343539 is about 25364.2176894932. The cubic root of 643343539 is about 863.2719861035.

The spelling of 643343539 in words is "six hundred forty-three million, three hundred forty-three thousand, five hundred thirty-nine".