21223105 has 4 divisors (see below), whose sum is σ = 25467732. Its totient is φ = 16978480.

The previous prime is 21223093. The next prime is 21223141. The reversal of 21223105 is 50132212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3448449 + 17774656 = 1857^2 + 4216^2 .

It is not a de Polignac number, because 21223105 - 2⁵ = 21223073 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2122306 + ... + 2122315.

It is an arithmetic number, because the mean of its divisors is an integer number (6366933).

Almost surely, 2^21223105 is an apocalyptic number.

It is an amenable number.

21223105 is a deficient number, since it is larger than the sum of its proper divisors (4244627).

21223105 is an equidigital number, since it uses as much as digits as its factorization.

21223105 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4244626.

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 21223105 is about 4606.8541327027. The cubic root of 21223105 is about 276.8660093013.

Adding to 21223105 its reverse (50132212), we get a palindrome (71355317).

The spelling of 21223105 in words is "twenty-one million, two hundred twenty-three thousand, one hundred five".