12071721 has 4 divisors (see below), whose sum is σ = 16095632. Its totient is φ = 8047812.

The previous prime is 12071713. The next prime is 12071729. The reversal of 12071721 is 12717021.

It is a happy number.

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 an interprime number because it is at equal distance from previous prime (12071713) and next prime (12071729).

It is not a de Polignac number, because 12071721 - 2³ = 12071713 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (12071729) 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, 2011951 + ... + 2011956.

It is an arithmetic number, because the mean of its divisors is an integer number (4023908).

Almost surely, 2^12071721 is an apocalyptic number.

It is an amenable number.

12071721 is a deficient number, since it is larger than the sum of its proper divisors (4023911).

12071721 is an equidigital number, since it uses as much as digits as its factorization.

12071721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4023910.

The product of its (nonzero) digits is 196, while the sum is 21.

The square root of 12071721 is about 3474.4382279730. The cubic root of 12071721 is about 229.3980542179.

Adding to 12071721 its reverse (12717021), we get a palindrome (24788742).

The spelling of 12071721 in words is "twelve million, seventy-one thousand, seven hundred twenty-one".