12218778 has 96 divisors (see below), whose sum is σ = 32078592. Its totient is φ = 3312000.

The previous prime is 12218777. The next prime is 12218783. The reversal of 12218778 is 87781221.

It is a happy number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (12218777) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 120928 + ... + 121028.

It is an arithmetic number, because the mean of its divisors is an integer number (334152).

Almost surely, 2^12218778 is an apocalyptic number.

12218778 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 12218778, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (16039296).

12218778 is an abundant number, since it is smaller than the sum of its proper divisors (19859814).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

12218778 is a wasteful number, since it uses less digits than its factorization.

12218778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 180 (or 177 counting only the distinct ones).

The product of its digits is 12544, while the sum is 36.

The square root of 12218778 is about 3495.5368686369. The cubic root of 12218778 is about 230.3258016646.

Adding to 12218778 its reverse (87781221), we get a palindrome (99999999).

It can be divided in two parts, 122187 and 78, that added together give a triangular number (122265 = T₄₉₄).

The spelling of 12218778 in words is "twelve million, two hundred eighteen thousand, seven hundred seventy-eight".