21002120112 has 80 divisors (see below), whose sum is σ = 55614690432. Its totient is φ = 6825546240.

The previous prime is 21002120089. The next prime is 21002120129. The reversal of 21002120112 is 21102120012.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4616623 + ... + 4621169.

Almost surely, 2^21002120112 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21002120112, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27807345216).

21002120112 is an abundant number, since it is smaller than the sum of its proper divisors (34612570320).

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

21002120112 is a wasteful number, since it uses less digits than its factorization.

21002120112 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6946 (or 6940 counting only the distinct ones).

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

Adding to 21002120112 its reverse (21102120012), we get a palindrome (42104240124).

It can be divided in two parts, 2100 and 2120112, that added together give a palindrome (2122212).

The spelling of 21002120112 in words is "twenty-one billion, two million, one hundred twenty thousand, one hundred twelve".