21444240211 has 4 divisors (see below), whose sum is σ = 22183696800. Its totient is φ = 20704783624.

The previous prime is 21444240193. The next prime is 21444240217. The reversal of 21444240211 is 11204244412.

It is a happy number.

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

It is not a de Polignac number, because 21444240211 - 2⁵ = 21444240179 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21444240217) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 369728251 + ... + 369728308.

It is an arithmetic number, because the mean of its divisors is an integer number (5545924200).

Almost surely, 2^21444240211 is an apocalyptic number.

21444240211 is a deficient number, since it is larger than the sum of its proper divisors (739456589).

21444240211 is an equidigital number, since it uses as much as digits as its factorization.

21444240211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 739456588.

The product of its (nonzero) digits is 2048, while the sum is 25.

Adding to 21444240211 its reverse (11204244412), we get a palindrome (32648484623).

The spelling of 21444240211 in words is "twenty-one billion, four hundred forty-four million, two hundred forty thousand, two hundred eleven".