21212011020209 has 2 divisors, whose sum is σ = 21212011020210. Its totient is φ = 21212011020208.

The previous prime is 21212011020131. The next prime is 21212011020247. The reversal of 21212011020209 is 90202011021212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14257398154609 + 6954612865600 = 3775897^2 + 2637160^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21212011020209 is a prime.

It is a super-2 number, since 2×21212011020209² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21212011220209) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10606005510104 + 10606005510105.

It is an arithmetic number, because the mean of its divisors is an integer number (10606005510105).

Almost surely, 2^{21212011020209} is an apocalyptic number.

It is an amenable number.

21212011020209 is a deficient number, since it is larger than the sum of its proper divisors (1).

21212011020209 is an equidigital number, since it uses as much as digits as its factorization.

21212011020209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 288, while the sum is 23.

The spelling of 21212011020209 in words is "twenty-one trillion, two hundred twelve billion, eleven million, twenty thousand, two hundred nine".