21121002112 has 64 divisors (see below), whose sum is σ = 48155097600. Its totient is φ = 9039227904.

The previous prime is 21121002107. The next prime is 21121002121. The reversal of 21121002112 is 21120012112.

It is a tau number, because it is divible by the number of its divisors (64).

It is a junction number, because it is equal to n+sod(n) for n = 21121002092 and 21121002101.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 640689 + ... + 672847.

It is an arithmetic number, because the mean of its divisors is an integer number (752423400).

Almost surely, 2^21121002112 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 21121002112, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24077548800).

21121002112 is an abundant number, since it is smaller than the sum of its proper divisors (27034095488).

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

21121002112 is an equidigital number, since it uses as much as digits as its factorization.

21121002112 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32913 (or 32901 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 21121002112 its reverse (21120012112), we get a palindrome (42241014224).

The spelling of 21121002112 in words is "twenty-one billion, one hundred twenty-one million, two thousand, one hundred twelve".