21212201211989 has 2 divisors, whose sum is σ = 21212201211990. Its totient is φ = 21212201211988.

The previous prime is 21212201211973. The next prime is 21212201212009. The reversal of 21212201211989 is 98911210221212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15469731852964 + 5742469359025 = 3933158^2 + 2396345^2 .

It is a cyclic number.

It is not a de Polignac number, because 21212201211989 - 2⁴ = 21212201211973 is a prime.

It is a super-2 number, since 2×21212201211989² (a number of 27 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21212201210989) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10606100605994 + 10606100605995.

It is an arithmetic number, because the mean of its divisors is an integer number (10606100605995).

Almost surely, 2^{21212201211989} is an apocalyptic number.

It is an amenable number.

21212201211989 is a deficient number, since it is larger than the sum of its proper divisors (1).

21212201211989 is an equidigital number, since it uses as much as digits as its factorization.

21212201211989 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 20736, while the sum is 41.

The spelling of 21212201211989 in words is "twenty-one trillion, two hundred twelve billion, two hundred one million, two hundred eleven thousand, nine hundred eighty-nine".