21111324202181 has 2 divisors, whose sum is σ = 21111324202182. Its totient is φ = 21111324202180.

The previous prime is 21111324202127. The next prime is 21111324202271. The reversal of 21111324202181 is 18120242311112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20818687562500 + 292636639681 = 4562750^2 + 540959^2 .

It is a cyclic number.

It is not a de Polignac number, because 21111324202181 - 2⁶ = 21111324202117 is a prime.

It is a super-2 number, since 2×21111324202181² (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 (21111324202781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10555662101090 + 10555662101091.

It is an arithmetic number, because the mean of its divisors is an integer number (10555662101091).

Almost surely, 2^{21111324202181} is an apocalyptic number.

It is an amenable number.

21111324202181 is a deficient number, since it is larger than the sum of its proper divisors (1).

21111324202181 is an equidigital number, since it uses as much as digits as its factorization.

21111324202181 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1536, while the sum is 29.

Adding to 21111324202181 its reverse (18120242311112), we get a palindrome (39231566513293).

The spelling of 21111324202181 in words is "twenty-one trillion, one hundred eleven billion, three hundred twenty-four million, two hundred two thousand, one hundred eighty-one".