643291 has 4 divisors (see below), whose sum is σ = 701784. Its totient is φ = 584800.

The previous prime is 643273. The next prime is 643301. The reversal of 643291 is 192346.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 643291 - 2⁹ = 642779 is a prime.

It is a d-powerful number, because it can be written as 6⁶ + 4⁶ + 2¹¹ + 3¹² + 9⁵ + 1 .

It is a Duffinian number.

It is a nialpdrome in base 15.

It is not an unprimeable number, because it can be changed into a prime (643231) 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, 29230 + ... + 29251.

It is an arithmetic number, because the mean of its divisors is an integer number (175446).

2⁶⁴³²⁹¹ is an apocalyptic number.

643291 is a deficient number, since it is larger than the sum of its proper divisors (58493).

643291 is a wasteful number, since it uses less digits than its factorization.

643291 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58492.

The product of its digits is 1296, while the sum is 25.

The square root of 643291 is about 802.0542375675. The cubic root of 643291 is about 86.3248485605.

The spelling of 643291 in words is "six hundred forty-three thousand, two hundred ninety-one".