21101201212009 has 2 divisors, whose sum is σ = 21101201212010. Its totient is φ = 21101201212008.

The previous prime is 21101201211997. The next prime is 21101201212019. The reversal of 21101201212009 is 90021210210112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20859361512025 + 241839699984 = 4567205^2 + 491772^2 .

It is a cyclic number.

It is not a de Polignac number, because 21101201212009 - 2²⁷ = 21101066994281 is a prime.

It is not a weakly prime, because it can be changed into another prime (21101201212019) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10550600606004 + 10550600606005.

It is an arithmetic number, because the mean of its divisors is an integer number (10550600606005).

Almost surely, 2^{21101201212009} is an apocalyptic number.

It is an amenable number.

21101201212009 is a deficient number, since it is larger than the sum of its proper divisors (1).

21101201212009 is an equidigital number, since it uses as much as digits as its factorization.

21101201212009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 144, while the sum is 22.

The spelling of 21101201212009 in words is "twenty-one trillion, one hundred one billion, two hundred one million, two hundred twelve thousand, nine".