11218561 has 4 divisors (see below), whose sum is σ = 11280724. Its totient is φ = 11156400.

The previous prime is 11218517. The next prime is 11218573. The reversal of 11218561 is 16581211.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 16581211 = 547 ⋅30313.

It can be written as a sum of positive squares in 2 ways, for example, as 2480625 + 8737936 = 1575^2 + 2956^2 .

It is a cyclic number.

It is not a de Polignac number, because 11218561 - 2⁷ = 11218433 is a prime.

It is a super-2 number, since 2×11218561² = 251712221821442, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11218261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30810 + ... + 31171.

It is an arithmetic number, because the mean of its divisors is an integer number (2820181).

Almost surely, 2^11218561 is an apocalyptic number.

It is an amenable number.

11218561 is a deficient number, since it is larger than the sum of its proper divisors (62163).

11218561 is an equidigital number, since it uses as much as digits as its factorization.

11218561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 62162.

The product of its digits is 480, while the sum is 25.

The square root of 11218561 is about 3349.4120379553. The cubic root of 11218561 is about 223.8613153553.

Adding to 11218561 its reverse (16581211), we get a palindrome (27799772).

The spelling of 11218561 in words is "eleven million, two hundred eighteen thousand, five hundred sixty-one".