21444305749 has 24 divisors (see below), whose sum is σ = 23181670680. Its totient is φ = 19828426752.

The previous prime is 21444305717. The next prime is 21444305761. The reversal of 21444305749 is 94750344412.

It can be written as a sum of positive squares in 4 ways, for example, as 6979432849 + 14464872900 = 83543^2 + 120270^2 .

It is not a de Polignac number, because 21444305749 - 2⁵ = 21444305717 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21444305549) 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 23 ways as a sum of consecutive naturals, for example, 2552047 + ... + 2560435.

It is an arithmetic number, because the mean of its divisors is an integer number (965902945).

Almost surely, 2^21444305749 is an apocalyptic number.

It is an amenable number.

21444305749 is a deficient number, since it is larger than the sum of its proper divisors (1737364931).

21444305749 is an equidigital number, since it uses as much as digits as its factorization.

21444305749 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8597 (or 8578 counting only the distinct ones).

The product of its (nonzero) digits is 483840, while the sum is 43.

The spelling of 21444305749 in words is "twenty-one billion, four hundred forty-four million, three hundred five thousand, seven hundred forty-nine".