21009585340189 has 2 divisors, whose sum is σ = 21009585340190. Its totient is φ = 21009585340188.

The previous prime is 21009585340181. The next prime is 21009585340207. The reversal of 21009585340189 is 98104358590012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20843635023289 + 165950316900 = 4565483^2 + 407370^2 .

It is a cyclic number.

It is not a de Polignac number, because 21009585340189 - 2³ = 21009585340181 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21009585340181) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10504792670094 + 10504792670095.

It is an arithmetic number, because the mean of its divisors is an integer number (10504792670095).

Almost surely, 2^{21009585340189} is an apocalyptic number.

It is an amenable number.

21009585340189 is a deficient number, since it is larger than the sum of its proper divisors (1).

21009585340189 is an equidigital number, since it uses as much as digits as its factorization.

21009585340189 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3110400, while the sum is 55.

The spelling of 21009585340189 in words is "twenty-one trillion, nine billion, five hundred eighty-five million, three hundred forty thousand, one hundred eighty-nine".