21110021212 has 96 divisors (see below), whose sum is σ = 44895674880. Its totient is φ = 8484030720.

The previous prime is 21110021173. The next prime is 21110021221. The reversal of 21110021212 is 21212001112.

It is a junction number, because it is equal to n+sod(n) for n = 21110021192 and 21110021201.

It is a congruent number.

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, 31936162 + ... + 31936822.

It is an arithmetic number, because the mean of its divisors is an integer number (467663280).

Almost surely, 2^21110021212 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 21110021212, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22447837440).

21110021212 is an abundant number, since it is smaller than the sum of its proper divisors (23785653668).

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

21110021212 is a wasteful number, since it uses less digits than its factorization.

21110021212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1211 (or 1209 counting only the distinct ones).

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

Adding to 21110021212 its reverse (21212001112), we get a palindrome (42322022324).

The spelling of 21110021212 in words is "twenty-one billion, one hundred ten million, twenty-one thousand, two hundred twelve".