12215440 has 80 divisors (see below), whose sum is σ = 30051648. Its totient is φ = 4612608.

The previous prime is 12215429. The next prime is 12215449. The reversal of 12215440 is 4451221.

It is a tau number, because it is divible by the number of its divisors (80).

It is not an unprimeable number, because it can be changed into a prime (12215449) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 182287 + ... + 182353.

Almost surely, 2^12215440 is an apocalyptic number.

12215440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 12215440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (15025824).

12215440 is an abundant number, since it is smaller than the sum of its proper divisors (17836208).

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

12215440 is a wasteful number, since it uses less digits than its factorization.

12215440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 176 (or 170 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 19.

The square root of 12215440 is about 3495.0593700251. The cubic root of 12215440 is about 230.3048258205.

Adding to 12215440 its reverse (4451221), we get a palindrome (16666661).

The spelling of 12215440 in words is "twelve million, two hundred fifteen thousand, four hundred forty".