21204421441 has 32 divisors (see below), whose sum is σ = 26067640320. Its totient is φ = 16855434816.

The previous prime is 21204421421. The next prime is 21204421457. The reversal of 21204421441 is 14412440212.

It is a happy number.

It is not a de Polignac number, because 21204421441 - 2⁹ = 21204420929 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21204421421) 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 31 ways as a sum of consecutive naturals, for example, 796575 + ... + 822763.

It is an arithmetic number, because the mean of its divisors is an integer number (814613760).

Almost surely, 2^21204421441 is an apocalyptic number.

It is an amenable number.

21204421441 is a deficient number, since it is larger than the sum of its proper divisors (4863218879).

21204421441 is a wasteful number, since it uses less digits than its factorization.

21204421441 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26373.

The product of its (nonzero) digits is 2048, while the sum is 25.

Adding to 21204421441 its reverse (14412440212), we get a palindrome (35616861653).

The spelling of 21204421441 in words is "twenty-one billion, two hundred four million, four hundred twenty-one thousand, four hundred forty-one".