23121209 has 2 divisors, whose sum is σ = 23121210. Its totient is φ = 23121208.

The previous prime is 23121193. The next prime is 23121247. The reversal of 23121209 is 90212132.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19404025 + 3717184 = 4405^2 + 1928^2 .

It is a cyclic number.

It is not a de Polignac number, because 23121209 - 2⁴ = 23121193 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (23129209) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11560604 + 11560605.

It is an arithmetic number, because the mean of its divisors is an integer number (11560605).

Almost surely, 2^23121209 is an apocalyptic number.

It is an amenable number.

23121209 is a deficient number, since it is larger than the sum of its proper divisors (1).

23121209 is an equidigital number, since it uses as much as digits as its factorization.

23121209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 216, while the sum is 20.

The square root of 23121209 is about 4808.4518298513. The cubic root of 23121209 is about 284.8853914886.

The spelling of 23121209 in words is "twenty-three million, one hundred twenty-one thousand, two hundred nine".