21144443209 has 8 divisors (see below), whose sum is σ = 22410353160. Its totient is φ = 19880990976.

The previous prime is 21144443147. The next prime is 21144443231. The reversal of 21144443209 is 90234444112.

It can be written as a sum of positive squares in 4 ways, for example, as 957716809 + 20186726400 = 30947^2 + 142080^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21144443209 - 2⁷ = 21144443081 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21144443269) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 596694 + ... + 631135.

It is an arithmetic number, because the mean of its divisors is an integer number (2801294145).

Almost surely, 2^21144443209 is an apocalyptic number.

It is an amenable number.

21144443209 is a deficient number, since it is larger than the sum of its proper divisors (1265909951).

21144443209 is a wasteful number, since it uses less digits than its factorization.

21144443209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1228859.

The product of its (nonzero) digits is 27648, while the sum is 34.

The spelling of 21144443209 in words is "twenty-one billion, one hundred forty-four million, four hundred forty-three thousand, two hundred nine".