21210120012 has 24 divisors (see below), whose sum is σ = 49492634800. Its totient is φ = 7069703616.

The previous prime is 21210120011. The next prime is 21210120017. The reversal of 21210120012 is 21002101212.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a self number, because there is not a number n which added to its sum of digits gives 21210120012.

It is not an unprimeable number, because it can be changed into a prime (21210120011) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 473814 + ... + 516642.

Almost surely, 2^21210120012 is an apocalyptic number.

It is an amenable number.

21210120012 is an abundant number, since it is smaller than the sum of its proper divisors (28282514788).

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

21210120012 is a wasteful number, since it uses less digits than its factorization.

21210120012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84105 (or 84103 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21210120012 its reverse (21002101212), we get a palindrome (42212221224).

It can be divided in two parts, 212101200 and 12, that added together give a palindrome (212101212).

The spelling of 21210120012 in words is "twenty-one billion, two hundred ten million, one hundred twenty thousand, twelve".