21243000241081 has 2 divisors, whose sum is σ = 21243000241082. Its totient is φ = 21243000241080.

The previous prime is 21243000241079. The next prime is 21243000241123. The reversal of 21243000241081 is 18014200034212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20818313418681 + 424686822400 = 4562709^2 + 651680^2 .

It is a cyclic number.

It is not a de Polignac number, because 21243000241081 - 2¹ = 21243000241079 is a prime.

It is a super-2 number, since 2×21243000241081² (a number of 27 digits) contains 22 as substring.

Together with 21243000241079, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21243000248081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10621500120540 + 10621500120541.

It is an arithmetic number, because the mean of its divisors is an integer number (10621500120541).

Almost surely, 2^{21243000241081} is an apocalyptic number.

It is an amenable number.

21243000241081 is a deficient number, since it is larger than the sum of its proper divisors (1).

21243000241081 is an equidigital number, since it uses as much as digits as its factorization.

21243000241081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3072, while the sum is 28.

Adding to 21243000241081 its reverse (18014200034212), we get a palindrome (39257200275293).

The spelling of 21243000241081 in words is "twenty-one trillion, two hundred forty-three billion, two hundred forty-one thousand, eighty-one".