12215771 has 4 divisors (see below), whose sum is σ = 12222792. Its totient is φ = 12208752.

The previous prime is 12215761. The next prime is 12215779. The reversal of 12215771 is 17751221.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 17751221 = 79 ⋅224699.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12215771 is a prime.

It is a super-2 number, since 2×12215771² = 298450122248882, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 12215771.

It is not an unprimeable number, because it can be changed into a prime (12215779) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1271 + ... + 5103.

It is an arithmetic number, because the mean of its divisors is an integer number (3055698).

Almost surely, 2^12215771 is an apocalyptic number.

12215771 is a deficient number, since it is larger than the sum of its proper divisors (7021).

12215771 is an equidigital number, since it uses as much as digits as its factorization.

12215771 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7020.

The product of its digits is 980, while the sum is 26.

The square root of 12215771 is about 3495.1067222619. The cubic root of 12215771 is about 230.3069059805.

Adding to 12215771 its reverse (17751221), we get a palindrome (29966992).

The spelling of 12215771 in words is "twelve million, two hundred fifteen thousand, seven hundred seventy-one".