643886 has 8 divisors (see below), whose sum is σ = 976080. Its totient is φ = 318528.

The previous prime is 643883. The next prime is 643889. The reversal of 643886 is 688346.

It is an interprime number because it is at equal distance from previous prime (643883) and next prime (643889).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643883) 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, 1466 + ... + 1853.

It is an arithmetic number, because the mean of its divisors is an integer number (122010).

2⁶⁴³⁸⁸⁶ is an apocalyptic number.

643886 is a deficient number, since it is larger than the sum of its proper divisors (332194).

643886 is a wasteful number, since it uses less digits than its factorization.

643886 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3418.

The product of its digits is 27648, while the sum is 35.

The square root of 643886 is about 802.4250743839. The cubic root of 643886 is about 86.3514552114.

The spelling of 643886 in words is "six hundred forty-three thousand, eight hundred eighty-six".