21001001112 has 512 divisors, whose sum is σ = 77075712000. Its totient is φ = 5143357440.

The previous prime is 21001001111. The next prime is 21001001141. The reversal of 21001001112 is 21110010012.

It is a happy number.

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 = 21001001094 and 21001001103.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001001111) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 19793062 + ... + 19794122.

It is an arithmetic number, because the mean of its divisors is an integer number (150538500).

Almost surely, 2^21001001112 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 21001001112, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38537856000).

21001001112 is an abundant number, since it is smaller than the sum of its proper divisors (56074710888).

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

21001001112 is a wasteful number, since it uses less digits than its factorization.

21001001112 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1168 (or 1158 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

Adding to 21001001112 its reverse (21110010012), we get a palindrome (42111011124).

The spelling of 21001001112 in words is "twenty-one billion, one million, one thousand, one hundred twelve".