21101101212220 has 96 divisors (see below), whose sum is σ = 47302404323328. Its totient is φ = 7888359232512.

The previous prime is 21101101212187. The next prime is 21101101212241. The reversal of 21101101212220 is 2221210110112.

It is a junction number, because it is equal to n+sod(n) for n = 21101101212194 and 21101101212203.

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, 11997727 + ... + 13643593.

It is an arithmetic number, because the mean of its divisors is an integer number (492733378368).

Almost surely, 2^{21101101212220} is an apocalyptic number.

21101101212220 is a gapful number since it is divisible by the number (20) 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 21101101212220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23651202161664).

21101101212220 is an abundant number, since it is smaller than the sum of its proper divisors (26201303111108).

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

21101101212220 is a wasteful number, since it uses less digits than its factorization.

21101101212220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1646539 (or 1646537 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 21101101212220 its reverse (2221210110112), we get a palindrome (23322311322332).

The spelling of 21101101212220 in words is "twenty-one trillion, one hundred one billion, one hundred one million, two hundred twelve thousand, two hundred twenty".