643105 has 4 divisors (see below), whose sum is σ = 771732. Its totient is φ = 514480.

The previous prime is 643099. The next prime is 643121. The reversal of 643105 is 501346.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 501346 = 2 ⋅250673.

It can be written as a sum of positive squares in 2 ways, for example, as 136161 + 506944 = 369^2 + 712^2 .

It is not a de Polignac number, because 643105 - 2⁵ = 643073 is a prime.

It is a Duffinian number.

It is an unprimeable 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 in 3 ways as a sum of consecutive naturals, for example, 64306 + ... + 64315.

It is an arithmetic number, because the mean of its divisors is an integer number (192933).

2⁶⁴³¹⁰⁵ is an apocalyptic number.

It is an amenable number.

643105 is a deficient number, since it is larger than the sum of its proper divisors (128627).

643105 is a wasteful number, since it uses less digits than its factorization.

643105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128626.

The product of its (nonzero) digits is 360, while the sum is 19.

The square root of 643105 is about 801.9382769266. The cubic root of 643105 is about 86.3165278215.

The spelling of 643105 in words is "six hundred forty-three thousand, one hundred five".