21121021201109 has 2 divisors, whose sum is σ = 21121021201110. Its totient is φ = 21121021201108.

The previous prime is 21121021201097. The next prime is 21121021201153. The reversal of 21121021201109 is 90110212012112.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12405258852100 + 8715762349009 = 3522110^2 + 2952247^2 .

It is a cyclic number.

It is not a de Polignac number, because 21121021201109 - 2¹⁶ = 21121021135573 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21121021203109) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560510600554 + 10560510600555.

It is an arithmetic number, because the mean of its divisors is an integer number (10560510600555).

Almost surely, 2^{21121021201109} is an apocalyptic number.

It is an amenable number.

21121021201109 is a deficient number, since it is larger than the sum of its proper divisors (1).

21121021201109 is an equidigital number, since it uses as much as digits as its factorization.

21121021201109 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 23.

The spelling of 21121021201109 in words is "twenty-one trillion, one hundred twenty-one billion, twenty-one million, two hundred one thousand, one hundred nine".