231121209 has 16 divisors (see below), whose sum is σ = 336487104. Its totient is φ = 139944000.

The previous prime is 231121207. The next prime is 231121217. The reversal of 231121209 is 902121132.

231121209 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 231121209 - 2¹ = 231121207 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (231121207) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 42759 + ... + 47859.

It is an arithmetic number, because the mean of its divisors is an integer number (21030444).

Almost surely, 2^231121209 is an apocalyptic number.

It is an amenable number.

231121209 is a deficient number, since it is larger than the sum of its proper divisors (105365895).

231121209 is a wasteful number, since it uses less digits than its factorization.

231121209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6488.

The product of its (nonzero) digits is 216, while the sum is 21.

The square root of 231121209 is about 15202.6711139852. The cubic root of 231121209 is about 613.6865431328.

The spelling of 231121209 in words is "two hundred thirty-one million, one hundred twenty-one thousand, two hundred nine".