21120012 has 18 divisors (see below), whose sum is σ = 53386788. Its totient is φ = 7039992.

The previous prime is 21119999. The next prime is 21120017. The reversal of 21120012 is 21002112.

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 21119976 and 21120003.

It is not an unprimeable number, because it can be changed into a prime (21120017) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 293298 + ... + 293369.

Almost surely, 2^21120012 is an apocalyptic number.

It is an amenable number.

21120012 is an abundant number, since it is smaller than the sum of its proper divisors (32266776).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21120012 is a wasteful number, since it uses less digits than its factorization.

21120012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 586677 (or 586672 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 21120012 is about 4595.6514228127. The cubic root of 21120012 is about 276.4169815521.

Adding to 21120012 its reverse (21002112), we get a palindrome (42122124).

It can be divided in two parts, 21 and 120012, that multiplied together give a palindrome (2520252).

The spelling of 21120012 in words is "twenty-one million, one hundred twenty thousand, twelve".