21021111012 has 96 divisors (see below), whose sum is σ = 54132624000. Its totient is φ = 6295936000.

The previous prime is 21021110989. The next prime is 21021111029. The reversal of 21021111012 is 21011112012.

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

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 10784614 + ... + 10786562.

It is an arithmetic number, because the mean of its divisors is an integer number (563881500).

Almost surely, 2^21021111012 is an apocalyptic number.

21021111012 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 21021111012, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27066312000).

21021111012 is an abundant number, since it is smaller than the sum of its proper divisors (33111512988).

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

21021111012 is a wasteful number, since it uses less digits than its factorization.

21021111012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2877 (or 2875 counting only the distinct ones).

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

Adding to 21021111012 its reverse (21011112012), we get a palindrome (42032223024).

The spelling of 21021111012 in words is "twenty-one billion, twenty-one million, one hundred eleven thousand, twelve".