21995305 has 4 divisors (see below), whose sum is σ = 26394372. Its totient is φ = 17596240.

The previous prime is 21995299. The next prime is 21995339. The reversal of 21995305 is 50359912.

It is a happy number.

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 10523536 + 11471769 = 3244^2 + 3387^2 .

It is not a de Polignac number, because 21995305 - 2⁷ = 21995177 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, 2199526 + ... + 2199535.

It is an arithmetic number, because the mean of its divisors is an integer number (6598593).

Almost surely, 2^21995305 is an apocalyptic number.

It is an amenable number.

21995305 is a deficient number, since it is larger than the sum of its proper divisors (4399067).

21995305 is an equidigital number, since it uses as much as digits as its factorization.

21995305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4399066.

The product of its (nonzero) digits is 12150, while the sum is 34.

The square root of 21995305 is about 4689.9152444367. The cubic root of 21995305 is about 280.1839989586.

The spelling of 21995305 in words is "twenty-one million, nine hundred ninety-five thousand, three hundred five".