21212263243247 has 2 divisors, whose sum is σ = 21212263243248. Its totient is φ = 21212263243246.

The previous prime is 21212263243169. The next prime is 21212263243273. The reversal of 21212263243247 is 74234236221212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21212263243247 - 2²⁰ = 21212262194671 is a prime.

It is a super-2 number, since 2×21212263243247² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21212263245247) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10606131621623 + 10606131621624.

It is an arithmetic number, because the mean of its divisors is an integer number (10606131621624).

Almost surely, 2^{21212263243247} is an apocalyptic number.

21212263243247 is a deficient number, since it is larger than the sum of its proper divisors (1).

21212263243247 is an equidigital number, since it uses as much as digits as its factorization.

21212263243247 is an evil number, because the sum of its binary digits is even.

The product of its digits is 387072, while the sum is 41.

Adding to 21212263243247 its reverse (74234236221212), we get a palindrome (95446499464459).

The spelling of 21212263243247 in words is "twenty-one trillion, two hundred twelve billion, two hundred sixty-three million, two hundred forty-three thousand, two hundred forty-seven".