12040021 has 4 divisors (see below), whose sum is σ = 13760032. Its totient is φ = 10320012.

The previous prime is 12040013. The next prime is 12040027. The reversal of 12040021 is 12004021.

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.

It is a cyclic number.

It is not a de Polignac number, because 12040021 - 2³ = 12040013 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 (12040027) 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, 859995 + ... + 860008.

It is an arithmetic number, because the mean of its divisors is an integer number (3440008).

Almost surely, 2^12040021 is an apocalyptic number.

It is an amenable number.

12040021 is a deficient number, since it is larger than the sum of its proper divisors (1720011).

12040021 is an equidigital number, since it uses as much as digits as its factorization.

12040021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1720010.

The product of its (nonzero) digits is 16, while the sum is 10.

The square root of 12040021 is about 3469.8733406279. The cubic root of 12040021 is about 229.1970805842.

Adding to 12040021 its reverse (12004021), we get a palindrome (24044042).

The spelling of 12040021 in words is "twelve million, forty thousand, twenty-one".