12213778 has 4 divisors (see below), whose sum is σ = 18320670. Its totient is φ = 6106888.

The previous prime is 12213739. The next prime is 12213779. The reversal of 12213778 is 87731221.

12213778 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 87731221 = 71 ⋅1235651.

It can be written as a sum of positive squares in only one way, i.e., 9566649 + 2647129 = 3093^2 + 1627^2 .

It is not an unprimeable number, because it can be changed into a prime (12213779) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3053443 + ... + 3053446.

Almost surely, 2^12213778 is an apocalyptic number.

12213778 is a deficient number, since it is larger than the sum of its proper divisors (6106892).

12213778 is an equidigital number, since it uses as much as digits as its factorization.

12213778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6106891.

The product of its digits is 4704, while the sum is 31.

The square root of 12213778 is about 3494.8215977357. The cubic root of 12213778 is about 230.2943804612.

Adding to 12213778 its reverse (87731221), we get a palindrome (99944999).

The spelling of 12213778 in words is "twelve million, two hundred thirteen thousand, seven hundred seventy-eight".