12840640 has 28 divisors (see below), whose sum is σ = 30577536. Its totient is φ = 5136128.

The previous prime is 12840631. The next prime is 12840643. The reversal of 12840640 is 4604821.

12840640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not an unprimeable number, because it can be changed into a prime (12840643) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19744 + ... + 20383.

Almost surely, 2^12840640 is an apocalyptic number.

12840640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

12840640 is an abundant number, since it is smaller than the sum of its proper divisors (17736896).

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

12840640 is an equidigital number, since it uses as much as digits as its factorization.

12840640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40144 (or 40134 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 25.

The square root of 12840640 is about 3583.3838756125. The cubic root of 12840640 is about 234.1687243451.

The spelling of 12840640 in words is "twelve million, eight hundred forty thousand, six hundred forty".