21380033971181 has 2 divisors, whose sum is σ = 21380033971182. Its totient is φ = 21380033971180.

The previous prime is 21380033971129. The next prime is 21380033971213. The reversal of 21380033971181 is 18117933008312.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18404391721156 + 2975642250025 = 4290034^2 + 1725005^2 .

It is a cyclic number.

It is not a de Polignac number, because 21380033971181 - 2¹⁸ = 21380033709037 is a prime.

It is a super-2 number, since 2×21380033971181² (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 (21380033971481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10690016985590 + 10690016985591.

It is an arithmetic number, because the mean of its divisors is an integer number (10690016985591).

Almost surely, 2^{21380033971181} is an apocalyptic number.

It is an amenable number.

21380033971181 is a deficient number, since it is larger than the sum of its proper divisors (1).

21380033971181 is an equidigital number, since it uses as much as digits as its factorization.

21380033971181 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 217728, while the sum is 47.

Adding to 21380033971181 its reverse (18117933008312), we get a palindrome (39497966979493).

The spelling of 21380033971181 in words is "twenty-one trillion, three hundred eighty billion, thirty-three million, nine hundred seventy-one thousand, one hundred eighty-one".