643106 has 4 divisors (see below), whose sum is σ = 964662. Its totient is φ = 321552.

The previous prime is 643099. The next prime is 643121. The reversal of 643106 is 601346.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 601346 = 2 ⋅300673.

It can be written as a sum of positive squares in only one way, i.e., 330625 + 312481 = 575^2 + 559^2 .

It is an Ulam number.

It is an unprimeable number.

643106 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160775 + ... + 160778.

2⁶⁴³¹⁰⁶ is an apocalyptic number.

643106 is a deficient number, since it is larger than the sum of its proper divisors (321556).

643106 is a wasteful number, since it uses less digits than its factorization.

643106 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 321555.

The product of its (nonzero) digits is 432, while the sum is 20.

The square root of 643106 is about 801.9389004157. The cubic root of 643106 is about 86.3165725609.

The spelling of 643106 in words is "six hundred forty-three thousand, one hundred six".