21001311012109 has 2 divisors, whose sum is σ = 21001311012110. Its totient is φ = 21001311012108.

The previous prime is 21001311012083. The next prime is 21001311012133. The reversal of 21001311012109 is 90121011310012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14104794253225 + 6896516758884 = 3755635^2 + 2626122^2 .

It is a cyclic number.

It is not a de Polignac number, because 21001311012109 - 2⁷ = 21001311011981 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21001311012109.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21001311012139) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500655506054 + 10500655506055.

It is an arithmetic number, because the mean of its divisors is an integer number (10500655506055).

Almost surely, 2^{21001311012109} is an apocalyptic number.

It is an amenable number.

21001311012109 is a deficient number, since it is larger than the sum of its proper divisors (1).

21001311012109 is an equidigital number, since it uses as much as digits as its factorization.

21001311012109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 108, while the sum is 22.

The spelling of 21001311012109 in words is "twenty-one trillion, one billion, three hundred eleven million, twelve thousand, one hundred nine".