21181158121273 has 2 divisors, whose sum is σ = 21181158121274. Its totient is φ = 21181158121272.

The previous prime is 21181158121267. The next prime is 21181158121423. The reversal of 21181158121273 is 37212185118112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20741493644089 + 439664477184 = 4554283^2 + 663072^2 .

It is a cyclic number.

It is not a de Polignac number, because 21181158121273 - 2⁹ = 21181158120761 is a prime.

It is not a weakly prime, because it can be changed into another prime (21181158121213) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10590579060636 + 10590579060637.

It is an arithmetic number, because the mean of its divisors is an integer number (10590579060637).

Almost surely, 2^{21181158121273} is an apocalyptic number.

It is an amenable number.

21181158121273 is a deficient number, since it is larger than the sum of its proper divisors (1).

21181158121273 is an equidigital number, since it uses as much as digits as its factorization.

21181158121273 is an evil number, because the sum of its binary digits is even.

The product of its digits is 53760, while the sum is 43.

The spelling of 21181158121273 in words is "twenty-one trillion, one hundred eighty-one billion, one hundred fifty-eight million, one hundred twenty-one thousand, two hundred seventy-three".