21111102012 has 192 divisors, whose sum is σ = 66796950528. Its totient is φ = 5011200000.

The previous prime is 21111101939. The next prime is 21111102017. The reversal of 21111102012 is 21020111112.

It is a super-2 number, since 2×21111102012² (a number of 21 digits) contains 22 as substring.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21111102017) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1204512 + ... + 1221912.

It is an arithmetic number, because the mean of its divisors is an integer number (347900784).

Almost surely, 2^21111102012 is an apocalyptic number.

21111102012 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21111102012, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33398475264).

21111102012 is an abundant number, since it is smaller than the sum of its proper divisors (45685848516).

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

21111102012 is a wasteful number, since it uses less digits than its factorization.

21111102012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17540 (or 17538 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 21111102012 its reverse (21020111112), we get a palindrome (42131213124).

The spelling of 21111102012 in words is "twenty-one billion, one hundred eleven million, one hundred two thousand, twelve".