12001000021 has 4 divisors (see below), whose sum is σ = 12074625952.
Its totient is φ = 11927374092.
The previous prime is 12001000003. The next prime is 12001000031. The reversal of 12001000021 is 12000010021.
Adding to 12001000021 its reverse (12000010021), we get a palindrome (24001010042).
It can be divided in two parts, 120010000 and 21, that added together give a palindrome (120010021).
12001000021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.
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: 12000010021 = 29 ⋅413793449.
It is a cyclic number.
It is not a de Polignac number, because 12001000021 - 27 = 12000999893 is a prime.
It is a Duffinian number.
It is a junction number, because it is equal to n+sod(n) for n = 12000999968 and 12001000013.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (12001000031) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (17) of ones.
It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 36812721 + ... + 36813046.
It is an arithmetic number, because the mean of its divisors is an integer number (3018656488).
Almost surely, 212001000021 is an apocalyptic number.
It is an amenable number.
12001000021 is a deficient number, since it is larger than the sum of its proper divisors (73625931).
12001000021 is an equidigital number, since it uses as much as digits as its factorization.
12001000021 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 73625930.
The product of its (nonzero) digits is 4, while the sum is 7.
The spelling of 12001000021 in words is "twelve billion, one million, twenty-one", and thus it is an aban number and an uban number.