22218261 has 16 divisors (see below), whose sum is σ = 32101440. Its totient is φ = 13668720.

The previous prime is 22218257. The next prime is 22218271. The reversal of 22218261 is 16281222.

It is not a de Polignac number, because 22218261 - 2² = 22218257 is a prime.

It is a super-2 number, since 2×22218261² = 987302243728242, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (22218211) 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, 4906 + ... + 8276.

It is an arithmetic number, because the mean of its divisors is an integer number (2006340).

Almost surely, 2^22218261 is an apocalyptic number.

It is an amenable number.

22218261 is a deficient number, since it is larger than the sum of its proper divisors (9883179).

22218261 is an equidigital number, since it uses as much as digits as its factorization.

22218261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3413 (or 3387 counting only the distinct ones).

The product of its digits is 768, while the sum is 24.

The square root of 22218261 is about 4713.6250381209. The cubic root of 22218261 is about 281.1275156535.

Adding to 22218261 its reverse (16281222), we get a palindrome (38499483).

The spelling of 22218261 in words is "twenty-two million, two hundred eighteen thousand, two hundred sixty-one".