12000021 has 16 divisors (see below), whose sum is σ = 17679360. Its totient is φ = 7179120.

The previous prime is 12000017. The next prime is 12000029.

It is a happy number.

12000021 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 12000021 - 2² = 12000017 is a prime.

12000021 is a modest number, since divided by 21 gives 12 as remainder.

It is a junction number, because it is equal to n+sod(n) for n = 11999973 and 12000009.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12000029) 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 15 ways as a sum of consecutive naturals, for example, 306 + ... + 4908.

It is an arithmetic number, because the mean of its divisors is an integer number (1104960).

Almost surely, 2^12000021 is an apocalyptic number.

12000021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

12000021 is a deficient number, since it is larger than the sum of its proper divisors (5679339).

12000021 is a wasteful number, since it uses less digits than its factorization.

12000021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4696.

The product of its (nonzero) digits is 4, while the sum is 6.

The square root of 12000021 is about 3464.1046462253. The cubic root of 12000021 is about 228.9429820606.

It can be divided in two parts, 120000 and 21, that added together give a palindrome (120021).

The spelling of 12000021 in words is "twelve million, twenty-one", and thus it is an aban number and an uban number.