105666521689 has 2 divisors, whose sum is σ = 105666521690. Its totient is φ = 105666521688.

The previous prime is 105666521687. The next prime is 105666521693. The reversal of 105666521689 is 986125666501.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 69000782400 + 36665739289 = 262680^2 + 191483^2 .

It is a cyclic number.

It is not a de Polignac number, because 105666521689 - 2¹ = 105666521687 is a prime.

It is a super-2 number, since 2×105666521689² (a number of 23 digits) contains 22 as substring.

Together with 105666521687, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (105666521687) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 52833260844 + 52833260845.

It is an arithmetic number, because the mean of its divisors is an integer number (52833260845).

Almost surely, 2^105666521689 is an apocalyptic number.

It is an amenable number.

105666521689 is a deficient number, since it is larger than the sum of its proper divisors (1).

105666521689 is an equidigital number, since it uses as much as digits as its factorization.

105666521689 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4665600, while the sum is 55.

The spelling of 105666521689 in words is "one hundred five billion, six hundred sixty-six million, five hundred twenty-one thousand, six hundred eighty-nine".