21111953012317 has 2 divisors, whose sum is σ = 21111953012318. Its totient is φ = 21111953012316.

The previous prime is 21111953012287. The next prime is 21111953012327. The reversal of 21111953012317 is 71321035911112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21111258900601 + 694111716 = 4594699^2 + 26346^2 .

It is a cyclic number.

It is not a de Polignac number, because 21111953012317 - 2¹⁵ = 21111952979549 is a prime.

It is a super-3 number, since 3×21111953012317³ (a number of 41 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21111953012327) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10555976506158 + 10555976506159.

It is an arithmetic number, because the mean of its divisors is an integer number (10555976506159).

Almost surely, 2^{21111953012317} is an apocalyptic number.

It is an amenable number.

21111953012317 is a deficient number, since it is larger than the sum of its proper divisors (1).

21111953012317 is an equidigital number, since it uses as much as digits as its factorization.

21111953012317 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11340, while the sum is 37.

Adding to 21111953012317 its reverse (71321035911112), we get a palindrome (92432988923429).

The spelling of 21111953012317 in words is "twenty-one trillion, one hundred eleven billion, nine hundred fifty-three million, twelve thousand, three hundred seventeen".