21144244441 has 2 divisors, whose sum is σ = 21144244442. Its totient is φ = 21144244440.

The previous prime is 21144244421. The next prime is 21144244447. The reversal of 21144244441 is 14444244112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11908265625 + 9235978816 = 109125^2 + 96104^2 .

It is a cyclic number.

It is not a de Polignac number, because 21144244441 - 2⁵ = 21144244409 is a prime.

It is not a weakly prime, because it can be changed into another prime (21144244447) 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 as a sum of consecutive naturals, namely, 10572122220 + 10572122221.

It is an arithmetic number, because the mean of its divisors is an integer number (10572122221).

Almost surely, 2^21144244441 is an apocalyptic number.

It is an amenable number.

21144244441 is a deficient number, since it is larger than the sum of its proper divisors (1).

21144244441 is an equidigital number, since it uses as much as digits as its factorization.

21144244441 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 16384, while the sum is 31.

Adding to 21144244441 its reverse (14444244112), we get a palindrome (35588488553).

The spelling of 21144244441 in words is "twenty-one billion, one hundred forty-four million, two hundred forty-four thousand, four hundred forty-one".