12821640 has 64 divisors (see below), whose sum is σ = 41428800. Its totient is φ = 3155712.

The previous prime is 12821629. The next prime is 12821659. The reversal of 12821640 is 4612821.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 12821640.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2550 + ... + 5669.

It is an arithmetic number, because the mean of its divisors is an integer number (647325).

Almost surely, 2^12821640 is an apocalyptic number.

12821640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

12821640 is an abundant number, since it is smaller than the sum of its proper divisors (28607160).

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

12821640 is a wasteful number, since it uses less digits than its factorization.

12821640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8246 (or 8242 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 24.

The square root of 12821640 is about 3580.7317687869. The cubic root of 12821640 is about 234.0531693045.

The spelling of 12821640 in words is "twelve million, eight hundred twenty-one thousand, six hundred forty".