21020244169 has 2 divisors, whose sum is σ = 21020244170. Its totient is φ = 21020244168.

The previous prime is 21020244109. The next prime is 21020244173. The reversal of 21020244169 is 96144202012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10567840000 + 10452404169 = 102800^2 + 102237^2 .

It is a cyclic number.

It is not a de Polignac number, because 21020244169 - 2⁷ = 21020244041 is a prime.

It is a super-2 number, since 2×21020244169² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21020244169.

It is not a weakly prime, because it can be changed into another prime (21020244109) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510122084 + 10510122085.

It is an arithmetic number, because the mean of its divisors is an integer number (10510122085).

Almost surely, 2^21020244169 is an apocalyptic number.

It is an amenable number.

21020244169 is a deficient number, since it is larger than the sum of its proper divisors (1).

21020244169 is an equidigital number, since it uses as much as digits as its factorization.

21020244169 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6912, while the sum is 31.

The spelling of 21020244169 in words is "twenty-one billion, twenty million, two hundred forty-four thousand, one hundred sixty-nine".