643437 has 8 divisors (see below), whose sum is σ = 953280. Its totient is φ = 428940.

The previous prime is 643429. The next prime is 643439. The reversal of 643437 is 734346.

643437 is nontrivially palindromic in base 15.

It is not a de Polignac number, because 643437 - 2³ = 643429 is a prime.

It is a super-2 number, since 2×643437² = 828022345938, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 23831 = 643437 / (6 + 4 + 3 + 4 + 3 + 7).

It is a self number, because there is not a number n which added to its sum of digits gives 643437.

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, 11889 + ... + 11942.

It is an arithmetic number, because the mean of its divisors is an integer number (119160).

2⁶⁴³⁴³⁷ is an apocalyptic number.

It is an amenable number.

643437 is a deficient number, since it is larger than the sum of its proper divisors (309843).

643437 is a wasteful number, since it uses less digits than its factorization.

643437 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23840 (or 23834 counting only the distinct ones).

The product of its digits is 6048, while the sum is 27.

The square root of 643437 is about 802.1452486925. The cubic root of 643437 is about 86.3313787698.

Subtracting 643437 from its reverse (734346), we obtain a palindrome (90909).

The spelling of 643437 in words is "six hundred forty-three thousand, four hundred thirty-seven".