21155143645169 has 2 divisors, whose sum is σ = 21155143645170. Its totient is φ = 21155143645168.

The previous prime is 21155143645087. The next prime is 21155143645213. The reversal of 21155143645169 is 96154634155112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11895221613025 + 9259922032144 = 3448945^2 + 3043012^2 .

It is a cyclic number.

It is not a de Polignac number, because 21155143645169 - 2⁴⁴ = 3562957600753 is a prime.

It is a super-2 number, since 2×21155143645169² (a number of 27 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21155143645169.

It is not a weakly prime, because it can be changed into another prime (21155133645169) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10577571822584 + 10577571822585.

It is an arithmetic number, because the mean of its divisors is an integer number (10577571822585).

Almost surely, 2^{21155143645169} is an apocalyptic number.

It is an amenable number.

21155143645169 is a deficient number, since it is larger than the sum of its proper divisors (1).

21155143645169 is an equidigital number, since it uses as much as digits as its factorization.

21155143645169 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3888000, while the sum is 53.

The spelling of 21155143645169 in words is "twenty-one trillion, one hundred fifty-five billion, one hundred forty-three million, six hundred forty-five thousand, one hundred sixty-nine".