21212212193 has 2 divisors, whose sum is σ = 21212212194. Its totient is φ = 21212212192.

The previous prime is 21212212187. The next prime is 21212212201. The reversal of 21212212193 is 39121221212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20137880464 + 1074331729 = 141908^2 + 32777^2 .

It is a cyclic number.

It is not a de Polignac number, because 21212212193 - 2¹² = 21212208097 is a prime.

It is a super-2 number, since 2×21212212193² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21212212393) 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, 10606106096 + 10606106097.

It is an arithmetic number, because the mean of its divisors is an integer number (10606106097).

Almost surely, 2^21212212193 is an apocalyptic number.

It is an amenable number.

21212212193 is a deficient number, since it is larger than the sum of its proper divisors (1).

21212212193 is an equidigital number, since it uses as much as digits as its factorization.

21212212193 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 864, while the sum is 26.

The spelling of 21212212193 in words is "twenty-one billion, two hundred twelve million, two hundred twelve thousand, one hundred ninety-three".