211017121209 has 12 divisors (see below), whose sum is σ = 309799271652. Its totient is φ = 138371882400.

The previous prime is 211017121207. The next prime is 211017121219. The reversal of 211017121209 is 902121710112.

It can be written as a sum of positive squares in 2 ways, for example, as 108791127225 + 102225993984 = 329835^2 + 319728^2 .

It is not a de Polignac number, because 211017121209 - 2¹ = 211017121207 is a prime.

It is not an unprimeable number, because it can be changed into a prime (211017121207) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 192182622 + ... + 192183719.

It is an arithmetic number, because the mean of its divisors is an integer number (25816605971).

Almost surely, 2^211017121209 is an apocalyptic number.

It is an amenable number.

211017121209 is a deficient number, since it is larger than the sum of its proper divisors (98782150443).

211017121209 is a wasteful number, since it uses less digits than its factorization.

211017121209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 384366408 (or 384366405 counting only the distinct ones).

The product of its (nonzero) digits is 504, while the sum is 27.

It can be divided in two parts, 21101 and 7121209, that added together give a triangular number (7142310 = T₃₇₇₉).

The spelling of 211017121209 in words is "two hundred eleven billion, seventeen million, one hundred twenty-one thousand, two hundred nine".