21444365 has 4 divisors (see below), whose sum is σ = 25733244. Its totient is φ = 17155488.

The previous prime is 21444347. The next prime is 21444373. The reversal of 21444365 is 56344412.

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 16048036 + 5396329 = 4006^2 + 2323^2 .

It is a cyclic number.

It is not a de Polignac number, because 21444365 - 2⁸ = 21444109 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2144432 + ... + 2144441.

It is an arithmetic number, because the mean of its divisors is an integer number (6433311).

Almost surely, 2^21444365 is an apocalyptic number.

It is an amenable number.

21444365 is a deficient number, since it is larger than the sum of its proper divisors (4288879).

21444365 is an equidigital number, since it uses as much as digits as its factorization.

21444365 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4288878.

The product of its digits is 11520, while the sum is 29.

The square root of 21444365 is about 4630.8060853376. The cubic root of 21444365 is about 277.8248340133.

Adding to 21444365 its reverse (56344412), we get a palindrome (77788777).

The spelling of 21444365 in words is "twenty-one million, four hundred forty-four thousand, three hundred sixty-five".