12809821 has 8 divisors (see below), whose sum is σ = 13047680. Its totient is φ = 12573792.

The previous prime is 12809813. The next prime is 12809843. The reversal of 12809821 is 12890821.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 12809821 - 2³ = 12809813 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12809221) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27436 + ... + 27898.

It is an arithmetic number, because the mean of its divisors is an integer number (1630960).

Almost surely, 2^12809821 is an apocalyptic number.

It is an amenable number.

12809821 is a deficient number, since it is larger than the sum of its proper divisors (237859).

12809821 is an equidigital number, since it uses as much as digits as its factorization.

12809821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 915.

The product of its (nonzero) digits is 2304, while the sum is 31.

The square root of 12809821 is about 3579.0810273030. The cubic root of 12809821 is about 233.9812303838.

The spelling of 12809821 in words is "twelve million, eight hundred nine thousand, eight hundred twenty-one".