643431 has 8 divisors (see below), whose sum is σ = 864640. Its totient is φ = 425592.

The previous prime is 643429. The next prime is 643439. The reversal of 643431 is 134346.

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

It is not a de Polignac number, because 643431 - 2¹ = 643429 is a prime.

It is a super-2 number, since 2×643431² = 828006903522, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 643398 and 643407.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643439) 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, 355 + ... + 1188.

It is an arithmetic number, because the mean of its divisors is an integer number (108080).

2⁶⁴³⁴³¹ is an apocalyptic number.

643431 is a deficient number, since it is larger than the sum of its proper divisors (221209).

643431 is a wasteful number, since it uses less digits than its factorization.

643431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1685.

The product of its digits is 864, while the sum is 21.

The square root of 643431 is about 802.1415087128. The cubic root of 643431 is about 86.3311104245.

Adding to 643431 its reverse (134346), we get a palindrome (777777).

The spelling of 643431 in words is "six hundred forty-three thousand, four hundred thirty-one".