12012721 has 4 divisors (see below), whose sum is σ = 13728832. Its totient is φ = 10296612.

The previous prime is 12012677. The next prime is 12012743. The reversal of 12012721 is 12721021.

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: 12721021 = 1459 ⋅8719.

It is a cyclic number.

It is not a de Polignac number, because 12012721 - 2¹³ = 12004529 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 12012695 and 12012704.

It is not an unprimeable number, because it can be changed into a prime (12012521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 858045 + ... + 858058.

It is an arithmetic number, because the mean of its divisors is an integer number (3432208).

Almost surely, 2^12012721 is an apocalyptic number.

It is an amenable number.

12012721 is a deficient number, since it is larger than the sum of its proper divisors (1716111).

12012721 is an equidigital number, since it uses as much as digits as its factorization.

12012721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1716110.

The product of its (nonzero) digits is 56, while the sum is 16.

The square root of 12012721 is about 3465.9372469795. The cubic root of 12012721 is about 229.0237194401.

Adding to 12012721 its reverse (12721021), we get a palindrome (24733742).

The spelling of 12012721 in words is "twelve million, twelve thousand, seven hundred twenty-one".