21011220021012 has 96 divisors (see below), whose sum is σ = 53809085635200. Its totient is φ = 6341184145920.

The previous prime is 21011220020993. The next prime is 21011220021013. The reversal of 21011220021012 is 21012002211012.

It is a junction number, because it is equal to n+sod(n) for n = 21011220020982 and 21011220021000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21011220021013) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 28499614 + ... + 29227562.

It is an arithmetic number, because the mean of its divisors is an integer number (560511308700).

Almost surely, 2^{21011220021012} 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 21011220021012, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26904542817600).

21011220021012 is an abundant number, since it is smaller than the sum of its proper divisors (32797865614188).

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

21011220021012 is a wasteful number, since it uses less digits than its factorization.

21011220021012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 731513 (or 731511 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21011220021012 its reverse (21012002211012), we get a palindrome (42023222232024).

The spelling of 21011220021012 in words is "twenty-one trillion, eleven billion, two hundred twenty million, twenty-one thousand, twelve".