21358423 has 4 divisors (see below), whose sum is σ = 21384720. Its totient is φ = 21332128.

The previous prime is 21358399. The next prime is 21358429. The reversal of 21358423 is 32485312.

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 21358423 - 2⁵ = 21358391 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21358391 and 21358400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21358429) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11890 + ... + 13567.

It is an arithmetic number, because the mean of its divisors is an integer number (5346180).

Almost surely, 2^21358423 is an apocalyptic number.

21358423 is a deficient number, since it is larger than the sum of its proper divisors (26297).

21358423 is an equidigital number, since it uses as much as digits as its factorization.

21358423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26296.

The product of its digits is 5760, while the sum is 28.

The square root of 21358423 is about 4621.5173915068. The cubic root of 21358423 is about 277.4531934149.

The spelling of 21358423 in words is "twenty-one million, three hundred fifty-eight thousand, four hundred twenty-three".