12211778 has 4 divisors (see below), whose sum is σ = 18317670. Its totient is φ = 6105888.

The previous prime is 12211757. The next prime is 12211789. The reversal of 12211778 is 87711221.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 87711221 = 13 ⋅6747017.

It can be written as a sum of positive squares in only one way, i.e., 7252249 + 4959529 = 2693^2 + 2227^2 .

It is a super-3 number, since 3×12211778³ (a number of 22 digits) contains 333 as substring.

It is a Curzon number.

It is a plaindrome in base 15.

It is a self number, because there is not a number n which added to its sum of digits gives 12211778.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 3052943 + ... + 3052946.

Almost surely, 2^12211778 is an apocalyptic number.

12211778 is a deficient number, since it is larger than the sum of its proper divisors (6105892).

12211778 is an equidigital number, since it uses as much as digits as its factorization.

12211778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6105891.

The product of its digits is 1568, while the sum is 29.

The square root of 12211778 is about 3494.5354483822. The cubic root of 12211778 is about 230.2818095787.

Adding to 12211778 its reverse (87711221), we get a palindrome (99922999).

The spelling of 12211778 in words is "twelve million, two hundred eleven thousand, seven hundred seventy-eight".