23218209 has 72 divisors (see below), whose sum is σ = 43748640. Its totient is φ = 11757312.

The previous prime is 23218193. The next prime is 23218219. The reversal of 23218209 is 90281232.

It is a happy number.

It is not a de Polignac number, because 23218209 - 2⁴ = 23218193 is a prime.

It is not an unprimeable number, because it can be changed into a prime (23218219) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 142362 + ... + 142524.

It is an arithmetic number, because the mean of its divisors is an integer number (607620).

Almost surely, 2^23218209 is an apocalyptic number.

It is an amenable number.

23218209 is a deficient number, since it is larger than the sum of its proper divisors (20530431).

23218209 is a wasteful number, since it uses less digits than its factorization.

23218209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 219 (or 209 counting only the distinct ones).

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

The square root of 23218209 is about 4818.5276796964. The cubic root of 23218209 is about 285.2832272132.

The spelling of 23218209 in words is "twenty-three million, two hundred eighteen thousand, two hundred nine".