21356458 has 16 divisors (see below), whose sum is σ = 33189120. Its totient is φ = 10296000.

The previous prime is 21356453. The next prime is 21356459. The reversal of 21356458 is 85465312.

It is not an unprimeable number, because it can be changed into a prime (21356453) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24433 + ... + 25291.

It is an arithmetic number, because the mean of its divisors is an integer number (2074320).

Almost surely, 2^21356458 is an apocalyptic number.

21356458 is a deficient number, since it is larger than the sum of its proper divisors (11832662).

21356458 is a wasteful number, since it uses less digits than its factorization.

21356458 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1293.

The product of its digits is 28800, while the sum is 34.

The square root of 21356458 is about 4621.3047941031. The cubic root of 21356458 is about 277.4446844807. Note that the first 3 decimals are identical.

The spelling of 21356458 in words is "twenty-one million, three hundred fifty-six thousand, four hundred fifty-eight".