21044209481 has 2 divisors, whose sum is σ = 21044209482. Its totient is φ = 21044209480.

The previous prime is 21044209457. The next prime is 21044209517. The reversal of 21044209481 is 18490244012.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20589667081 + 454542400 = 143491^2 + 21320^2 .

It is a cyclic number.

It is not a de Polignac number, because 21044209481 - 2¹⁴ = 21044193097 is a prime.

It is a super-3 number, since 3×21044209481³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is not a weakly prime, because it can be changed into another prime (21044209181) 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, 10522104740 + 10522104741.

It is an arithmetic number, because the mean of its divisors is an integer number (10522104741).

Almost surely, 2^21044209481 is an apocalyptic number.

It is an amenable number.

21044209481 is a deficient number, since it is larger than the sum of its proper divisors (1).

21044209481 is an equidigital number, since it uses as much as digits as its factorization.

21044209481 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 18432, while the sum is 35.

The spelling of 21044209481 in words is "twenty-one billion, forty-four million, two hundred nine thousand, four hundred eighty-one".