12216520 has 16 divisors (see below), whose sum is σ = 27487260. Its totient is φ = 4886592.

The previous prime is 12216499. The next prime is 12216539. The reversal of 12216520 is 2561221.

It can be written as a sum of positive squares in 2 ways, for example, as 10903204 + 1313316 = 3302^2 + 1146^2 .

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 in 3 ways as a sum of consecutive naturals, for example, 152667 + ... + 152746.

Almost surely, 2^12216520 is an apocalyptic number.

12216520 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

12216520 is an abundant number, since it is smaller than the sum of its proper divisors (15270740).

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

12216520 is a wasteful number, since it uses less digits than its factorization.

12216520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 305424 (or 305420 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 19.

The square root of 12216520 is about 3495.2138704234. The cubic root of 12216520 is about 230.3116129108.

Adding to 12216520 its reverse (2561221), we get a palindrome (14777741).

The spelling of 12216520 in words is "twelve million, two hundred sixteen thousand, five hundred twenty".