21447204073 has 2 divisors, whose sum is σ = 21447204074. Its totient is φ = 21447204072.

The previous prime is 21447204071. The next prime is 21447204089. The reversal of 21447204073 is 37040274412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17395499664 + 4051704409 = 131892^2 + 63653^2 .

It is a cyclic number.

It is not a de Polignac number, because 21447204073 - 2¹ = 21447204071 is a prime.

Together with 21447204071, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21447204071) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10723602036 + 10723602037.

It is an arithmetic number, because the mean of its divisors is an integer number (10723602037).

Almost surely, 2^21447204073 is an apocalyptic number.

It is an amenable number.

21447204073 is a deficient number, since it is larger than the sum of its proper divisors (1).

21447204073 is an equidigital number, since it uses as much as digits as its factorization.

21447204073 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 37632, while the sum is 34.

Adding to 21447204073 its reverse (37040274412), we get a palindrome (58487478485).

The spelling of 21447204073 in words is "twenty-one billion, four hundred forty-seven million, two hundred four thousand, seventy-three".