12812421 has 4 divisors (see below), whose sum is σ = 17083232. Its totient is φ = 8541612.

The previous prime is 12812419. The next prime is 12812473. The reversal of 12812421 is 12421821.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12421821 = 3 ⋅4140607.

It is not a de Polignac number, because 12812421 - 2¹ = 12812419 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12812411) 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, 2135401 + ... + 2135406.

It is an arithmetic number, because the mean of its divisors is an integer number (4270808).

Almost surely, 2^12812421 is an apocalyptic number.

It is an amenable number.

12812421 is a deficient number, since it is larger than the sum of its proper divisors (4270811).

12812421 is an equidigital number, since it uses as much as digits as its factorization.

12812421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4270810.

The product of its digits is 256, while the sum is 21.

The square root of 12812421 is about 3579.4442306034. Note that the first 3 decimals coincide. The cubic root of 12812421 is about 233.9970596460.

The spelling of 12812421 in words is "twelve million, eight hundred twelve thousand, four hundred twenty-one".