21458

21458 is an even natural number that sits between 21457 and 21459.

Its prime factorization is 2 × 10729, where 10729 is a prime number. Therefore, 21458 is a semiprime, and its positive divisors are 1, 2, 10729, and 21458.

The digit sum of 21458 is 20, so it is not divisible by 3 or 9. It is not divisible by 5, and its remainder modulo 4 is 2. It is also not a perfect square or a cube.

In binary, 21458 is represented as 101001111010010.

There is no widely recognized historical or mathematical significance attached to this number beyond its role as a concrete example of a semiprime.