211221212220989 has 2 divisors, whose sum is σ = 211221212220990. Its totient is φ = 211221212220988.

The previous prime is 211221212220971. The next prime is 211221212221051. The reversal of 211221212220989 is 989022212122112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 195439002002500 + 15782210218489 = 13979950^2 + 3972683^2 .

It is a cyclic number.

It is not a de Polignac number, because 211221212220989 - 2²⁴ = 211221195443773 is a prime.

It is a super-2 number, since 2×211221212220989² (a number of 29 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (211221212220959) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105610606110494 + 105610606110495.

It is an arithmetic number, because the mean of its divisors is an integer number (105610606110495).

Almost surely, 2^{211221212220989} is an apocalyptic number.

It is an amenable number.

211221212220989 is a deficient number, since it is larger than the sum of its proper divisors (1).

211221212220989 is an equidigital number, since it uses as much as digits as its factorization.

211221212220989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 82944, while the sum is 44.

The spelling of 211221212220989 in words is "two hundred eleven trillion, two hundred twenty-one billion, two hundred twelve million, two hundred twenty thousand, nine hundred eighty-nine".