12005921 has 4 divisors (see below), whose sum is σ = 12013872. Its totient is φ = 11997972.

The previous prime is 12005909. The next prime is 12005923. The reversal of 12005921 is 12950021.

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 a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 12005921 - 2⁶ = 12005857 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a nialpdrome in base 16.

It is a junction number, because it is equal to n+sod(n) for n = 12005893 and 12005902.

It is not an unprimeable number, because it can be changed into a prime (12005923) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 935 + ... + 4988.

It is an arithmetic number, because the mean of its divisors is an integer number (3003468).

Almost surely, 2^12005921 is an apocalyptic number.

It is an amenable number.

12005921 is a deficient number, since it is larger than the sum of its proper divisors (7951).

12005921 is an equidigital number, since it uses as much as digits as its factorization.

12005921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7950.

The product of its (nonzero) digits is 180, while the sum is 20.

The square root of 12005921 is about 3464.9561324784. The cubic root of 12005921 is about 228.9804970583.

Adding to 12005921 its reverse (12950021), we get a palindrome (24955942).

The spelling of 12005921 in words is "twelve million, five thousand, nine hundred twenty-one".