21121211110009 has 2 divisors, whose sum is σ = 21121211110010. Its totient is φ = 21121211110008.

The previous prime is 21121211109991. The next prime is 21121211110033. The reversal of 21121211110009 is 90001111212112.

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., 20702472700009 + 418738410000 = 4549997^2 + 647100^2 .

It is a cyclic number.

It is not a de Polignac number, because 21121211110009 - 2¹⁷ = 21121210978937 is a prime.

It is a super-2 number, since 2×21121211110009² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21121211110409) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560605555004 + 10560605555005.

It is an arithmetic number, because the mean of its divisors is an integer number (10560605555005).

Almost surely, 2^{21121211110009} is an apocalyptic number.

It is an amenable number.

21121211110009 is a deficient number, since it is larger than the sum of its proper divisors (1).

21121211110009 is an equidigital number, since it uses as much as digits as its factorization.

21121211110009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72, while the sum is 22.

The spelling of 21121211110009 in words is "twenty-one trillion, one hundred twenty-one billion, two hundred eleven million, one hundred ten thousand, nine".