212164209 has 6 divisors (see below), whose sum is σ = 306459426. Its totient is φ = 141442800.

The previous prime is 212164189. The next prime is 212164219. The reversal of 212164209 is 902461212.

212164209 is a `hidden beast` number, since 2 + 12 + 1 + 642 + 0 + 9 = 666.

It can be written as a sum of positive squares in only one way, i.e., 177023025 + 35141184 = 13305^2 + 5928^2 .

It is not a de Polignac number, because 212164209 - 2⁹ = 212163697 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (212164219) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 11786892 + ... + 11786909.

It is an arithmetic number, because the mean of its divisors is an integer number (51076571).

Almost surely, 2^212164209 is an apocalyptic number.

It is an amenable number.

212164209 is a deficient number, since it is larger than the sum of its proper divisors (94295217).

212164209 is a wasteful number, since it uses less digits than its factorization.

212164209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23573807 (or 23573804 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 212164209 is about 14565.8576472517. The cubic root of 212164209 is about 596.4271079690.

It can be divided in two parts, 21216 and 4209, that added together give a triangular number (25425 = T₂₂₅).

The spelling of 212164209 in words is "two hundred twelve million, one hundred sixty-four thousand, two hundred nine".