21718285676869 has 2 divisors, whose sum is σ = 21718285676870. Its totient is φ = 21718285676868.

The previous prime is 21718285676849. The next prime is 21718285676891. The reversal of 21718285676869 is 96867658281712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15326050522500 + 6392235154369 = 3914850^2 + 2528287^2 .

It is a cyclic number.

It is not a de Polignac number, because 21718285676869 - 2²³ = 21718277288261 is a prime.

It is a super-2 number, since 2×21718285676869² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21718285676795 and 21718285676804.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21718285676809) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10859142838434 + 10859142838435.

It is an arithmetic number, because the mean of its divisors is an integer number (10859142838435).

Almost surely, 2^{21718285676869} is an apocalyptic number.

It is an amenable number.

21718285676869 is a deficient number, since it is larger than the sum of its proper divisors (1).

21718285676869 is an equidigital number, since it uses as much as digits as its factorization.

21718285676869 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 975421440, while the sum is 76.

The spelling of 21718285676869 in words is "twenty-one trillion, seven hundred eighteen billion, two hundred eighty-five million, six hundred seventy-six thousand, eight hundred sixty-nine".