21345013447 has 2 divisors, whose sum is σ = 21345013448. Its totient is φ = 21345013446.

The previous prime is 21345013381. The next prime is 21345013457. The reversal of 21345013447 is 74431054312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21345013447 - 2¹¹ = 21345011399 is a prime.

It is a super-2 number, since 2×21345013447² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21345013457) 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, 10672506723 + 10672506724.

It is an arithmetic number, because the mean of its divisors is an integer number (10672506724).

Almost surely, 2^21345013447 is an apocalyptic number.

21345013447 is a deficient number, since it is larger than the sum of its proper divisors (1).

21345013447 is an equidigital number, since it uses as much as digits as its factorization.

21345013447 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 40320, while the sum is 34.

Adding to 21345013447 its reverse (74431054312), we get a palindrome (95776067759).

The spelling of 21345013447 in words is "twenty-one billion, three hundred forty-five million, thirteen thousand, four hundred forty-seven".