211123409 has 12 divisors (see below), whose sum is σ = 246233844. Its totient is φ = 180490464.

The previous prime is 211123387. The next prime is 211123411. The reversal of 211123409 is 904321112.

It can be written as a sum of positive squares in 2 ways, for example, as 127803025 + 83320384 = 11305^2 + 9128^2 .

It is not a de Polignac number, because 211123409 - 2²⁰ = 210074833 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211123909) 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, 14027 + ... + 24879.

It is an arithmetic number, because the mean of its divisors is an integer number (20519487).

Almost surely, 2^211123409 is an apocalyptic number.

It is an amenable number.

211123409 is a deficient number, since it is larger than the sum of its proper divisors (35110435).

211123409 is a wasteful number, since it uses less digits than its factorization.

211123409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11264 (or 11257 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 211123409 is about 14530.0863383533. The cubic root of 211123409 is about 595.4502244057.

The spelling of 211123409 in words is "two hundred eleven million, one hundred twenty-three thousand, four hundred nine".