21444389 has 2 divisors, whose sum is σ = 21444390. Its totient is φ = 21444388.

The previous prime is 21444373. The next prime is 21444413. The reversal of 21444389 is 98344412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15602500 + 5841889 = 3950^2 + 2417^2 .

It is a cyclic number.

It is not a de Polignac number, because 21444389 - 2⁴ = 21444373 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21444289) by changing a digit.

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 as a sum of consecutive naturals, namely, 10722194 + 10722195.

It is an arithmetic number, because the mean of its divisors is an integer number (10722195).

Almost surely, 2^21444389 is an apocalyptic number.

It is an amenable number.

21444389 is a deficient number, since it is larger than the sum of its proper divisors (1).

21444389 is an equidigital number, since it uses as much as digits as its factorization.

21444389 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 27648, while the sum is 35.

The square root of 21444389 is about 4630.8086766784. The cubic root of 21444389 is about 277.8249376581.

The spelling of 21444389 in words is "twenty-one million, four hundred forty-four thousand, three hundred eighty-nine".