212101209 has 24 divisors (see below), whose sum is σ = 313037504. Its totient is φ = 138348000.

The previous prime is 212101207. The next prime is 212101223. The reversal of 212101209 is 902101212.

It is not a de Polignac number, because 212101209 - 2¹ = 212101207 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 212101191 and 212101200.

It is not an unprimeable number, because it can be changed into a prime (212101207) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 114924 + ... + 116754.

Almost surely, 2^212101209 is an apocalyptic number.

It is an amenable number.

212101209 is a deficient number, since it is larger than the sum of its proper divisors (100936295).

212101209 is a wasteful number, since it uses less digits than its factorization.

212101209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2109 (or 2106 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 18.

The square root of 212101209 is about 14563.6948951837. The cubic root of 212101209 is about 596.3680678074.

The spelling of 212101209 in words is "two hundred twelve million, one hundred one thousand, two hundred nine".