643279 has 8 divisors (see below), whose sum is σ = 791840. Its totient is φ = 508896.

The previous prime is 643273. The next prime is 643301. The reversal of 643279 is 972346.

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

It is a cyclic number.

It is not a de Polignac number, because 643279 - 2¹³ = 635087 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 643279.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643273) 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 7 ways as a sum of consecutive naturals, for example, 3444 + ... + 3625.

It is an arithmetic number, because the mean of its divisors is an integer number (98980).

2⁶⁴³²⁷⁹ is an apocalyptic number.

643279 is a deficient number, since it is larger than the sum of its proper divisors (148561).

643279 is a wasteful number, since it uses less digits than its factorization.

643279 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7089.

The product of its digits is 9072, while the sum is 31.

The square root of 643279 is about 802.0467567418. The cubic root of 643279 is about 86.3243117870.

The spelling of 643279 in words is "six hundred forty-three thousand, two hundred seventy-nine".