21102121211009 has 2 divisors, whose sum is σ = 21102121211010. Its totient is φ = 21102121211008.

The previous prime is 21102121210997. The next prime is 21102121211089. The reversal of 21102121211009 is 90011212120112.

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., 20827175142400 + 274946068609 = 4563680^2 + 524353^2 .

It is a cyclic number.

It is not a de Polignac number, because 21102121211009 - 2¹⁶ = 21102121145473 is a prime.

It is not a weakly prime, because it can be changed into another prime (21102121211089) 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, 10551060605504 + 10551060605505.

It is an arithmetic number, because the mean of its divisors is an integer number (10551060605505).

Almost surely, 2^{21102121211009} is an apocalyptic number.

It is an amenable number.

21102121211009 is a deficient number, since it is larger than the sum of its proper divisors (1).

21102121211009 is an equidigital number, since it uses as much as digits as its factorization.

21102121211009 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 21102121211009 in words is "twenty-one trillion, one hundred two billion, one hundred twenty-one million, two hundred eleven thousand, nine".