12215665 has 16 divisors (see below), whose sum is σ = 18276480. Its totient is φ = 7614720.

The previous prime is 12215657. The next prime is 12215681. The reversal of 12215665 is 56651221.

It is not a de Polignac number, because 12215665 - 2³ = 12215657 is a prime.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 15480 + ... + 16249.

It is an arithmetic number, because the mean of its divisors is an integer number (1142280).

Almost surely, 2^12215665 is an apocalyptic number.

It is an amenable number.

12215665 is a deficient number, since it is larger than the sum of its proper divisors (6060815).

12215665 is a wasteful number, since it uses less digits than its factorization.

12215665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31752.

The product of its digits is 3600, while the sum is 28.

The square root of 12215665 is about 3495.0915581713. The cubic root of 12215665 is about 230.3062398307.

Adding to 12215665 its reverse (56651221), we get a palindrome (68866886).

Subtracting 12215665 from its reverse (56651221), we obtain a square (44435556 = 6666²).

It can be divided in two parts, 122156 and 65, that added together give a palindrome (122221).

The spelling of 12215665 in words is "twelve million, two hundred fifteen thousand, six hundred sixty-five".