21236303447 has 2 divisors, whose sum is σ = 21236303448. Its totient is φ = 21236303446.

The previous prime is 21236303377. The next prime is 21236303449. The reversal of 21236303447 is 74430363212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21236303447 - 2⁸ = 21236303191 is a prime.

Together with 21236303449, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21236303449) 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, 10618151723 + 10618151724.

It is an arithmetic number, because the mean of its divisors is an integer number (10618151724).

Almost surely, 2^21236303447 is an apocalyptic number.

21236303447 is a deficient number, since it is larger than the sum of its proper divisors (1).

21236303447 is an equidigital number, since it uses as much as digits as its factorization.

21236303447 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72576, while the sum is 35.

Adding to 21236303447 its reverse (74430363212), we get a palindrome (95666666659).

The spelling of 21236303447 in words is "twenty-one billion, two hundred thirty-six million, three hundred three thousand, four hundred forty-seven".