211231209989 has 2 divisors, whose sum is σ = 211231209990. Its totient is φ = 211231209988.

The previous prime is 211231209911. The next prime is 211231209991. The reversal of 211231209989 is 989902132112.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 185644648225 + 25586561764 = 430865^2 + 159958^2 .

It is a cyclic number.

It is not a de Polignac number, because 211231209989 - 2¹² = 211231205893 is a prime.

Together with 211231209991, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (211231209289) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105615604994 + 105615604995.

It is an arithmetic number, because the mean of its divisors is an integer number (105615604995).

Almost surely, 2^211231209989 is an apocalyptic number.

It is an amenable number.

211231209989 is a deficient number, since it is larger than the sum of its proper divisors (1).

211231209989 is an equidigital number, since it uses as much as digits as its factorization.

211231209989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 139968, while the sum is 47.

The spelling of 211231209989 in words is "two hundred eleven billion, two hundred thirty-one million, two hundred nine thousand, nine hundred eighty-nine".