21002166606101 has 2 divisors, whose sum is σ = 21002166606102. Its totient is φ = 21002166606100.

The previous prime is 21002166606097. The next prime is 21002166606119. The reversal of 21002166606101 is 10160666120012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13673532555076 + 7328634051025 = 3697774^2 + 2707145^2 .

It is a cyclic number.

It is not a de Polignac number, because 21002166606101 - 2² = 21002166606097 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21002166606131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10501083303050 + 10501083303051.

It is an arithmetic number, because the mean of its divisors is an integer number (10501083303051).

Almost surely, 2^{21002166606101} is an apocalyptic number.

It is an amenable number.

21002166606101 is a deficient number, since it is larger than the sum of its proper divisors (1).

21002166606101 is an equidigital number, since it uses as much as digits as its factorization.

21002166606101 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5184, while the sum is 32.

The spelling of 21002166606101 in words is "twenty-one trillion, two billion, one hundred sixty-six million, six hundred six thousand, one hundred one".