643706 has 8 divisors (see below), whose sum is σ = 1103520. Its totient is φ = 275868.

The previous prime is 643703. The next prime is 643723. The reversal of 643706 is 607346.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (643703) 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 3 ways as a sum of consecutive naturals, for example, 22976 + ... + 23003.

It is an arithmetic number, because the mean of its divisors is an integer number (137940).

2⁶⁴³⁷⁰⁶ is an apocalyptic number.

643706 is a deficient number, since it is larger than the sum of its proper divisors (459814).

643706 is a wasteful number, since it uses less digits than its factorization.

643706 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45988.

The product of its (nonzero) digits is 3024, while the sum is 26.

The square root of 643706 is about 802.3129065396. The cubic root of 643706 is about 86.3434078704.

The spelling of 643706 in words is "six hundred forty-three thousand, seven hundred six".