21122305 has 4 divisors (see below), whose sum is σ = 25346772. Its totient is φ = 16897840.

The previous prime is 21122291. The next prime is 21122323. The reversal of 21122305 is 50322112.

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 15085456 + 6036849 = 3884^2 + 2457^2 .

It is not a de Polignac number, because 21122305 - 2¹¹ = 21120257 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, 2112226 + ... + 2112235.

It is an arithmetic number, because the mean of its divisors is an integer number (6336693).

Almost surely, 2^21122305 is an apocalyptic number.

It is an amenable number.

21122305 is a deficient number, since it is larger than the sum of its proper divisors (4224467).

21122305 is an equidigital number, since it uses as much as digits as its factorization.

21122305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4224466.

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

The square root of 21122305 is about 4595.9008910115. The cubic root of 21122305 is about 276.4269847220.

Adding to 21122305 its reverse (50322112), we get a palindrome (71444417).

The spelling of 21122305 in words is "twenty-one million, one hundred twenty-two thousand, three hundred five".