12656640 has 112 divisors (see below), whose sum is σ = 40891968. Its totient is φ = 3342336.

The previous prime is 12656639. The next prime is 12656671. The reversal of 12656640 is 4665621.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 12656598 and 12656607.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 122829 + ... + 122931.

Almost surely, 2^12656640 is an apocalyptic number.

12656640 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 12656640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20445984).

12656640 is an abundant number, since it is smaller than the sum of its proper divisors (28235328).

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

12656640 is an equidigital number, since it uses as much as digits as its factorization.

12656640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 137 (or 113 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 30.

The square root of 12656640 is about 3557.6171800799. The cubic root of 12656640 is about 233.0448316418.

The spelling of 12656640 in words is "twelve million, six hundred fifty-six thousand, six hundred forty".