21211211111197 has 2 divisors, whose sum is σ = 21211211111198. Its totient is φ = 21211211111196.

The previous prime is 21211211111179. The next prime is 21211211111231. The reversal of 21211211111197 is 79111111211212.

Together with previous prime (21211211111179) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21105442412356 + 105768698841 = 4594066^2 + 325221^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21211211111197 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21211211111117) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10605605555598 + 10605605555599.

It is an arithmetic number, because the mean of its divisors is an integer number (10605605555599).

Almost surely, 2^{21211211111197} is an apocalyptic number.

It is an amenable number.

21211211111197 is a deficient number, since it is larger than the sum of its proper divisors (1).

21211211111197 is an equidigital number, since it uses as much as digits as its factorization.

21211211111197 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 504, while the sum is 31.

The spelling of 21211211111197 in words is "twenty-one trillion, two hundred eleven billion, two hundred eleven million, one hundred eleven thousand, one hundred ninety-seven".