12216981 has 32 divisors (see below), whose sum is σ = 19932160. Its totient is φ = 6500736.

The previous prime is 12216959. The next prime is 12216983. The reversal of 12216981 is 18961221.

It is a happy number.

It is not a de Polignac number, because 12216981 - 2⁵ = 12216949 is a prime.

It is a super-2 number, since 2×12216981² = 298509249508722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12216983) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 26505 + ... + 26961.

It is an arithmetic number, because the mean of its divisors is an integer number (622880).

Almost surely, 2^12216981 is an apocalyptic number.

It is an amenable number.

12216981 is a deficient number, since it is larger than the sum of its proper divisors (7715179).

12216981 is a wasteful number, since it uses less digits than its factorization.

12216981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 553.

The product of its digits is 1728, while the sum is 30.

The square root of 12216981 is about 3495.2798171248. The cubic root of 12216981 is about 230.3145098710.

The spelling of 12216981 in words is "twelve million, two hundred sixteen thousand, nine hundred eighty-one".