21101101112220 has 96 divisors (see below), whose sum is σ = 60710690956608. Its totient is φ = 5472104251392.

The previous prime is 21101101112213. The next prime is 21101101112227. The reversal of 21101101112220 is 2221110110112.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21101101112213) and next prime (21101101112227).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21101101112220.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21101101112227) 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, 1971292 + ... + 6788828.

It is an arithmetic number, because the mean of its divisors is an integer number (632403030798).

Almost surely, 2^{21101101112220} is an apocalyptic number.

21101101112220 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 21101101112220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30355345478304).

21101101112220 is an abundant number, since it is smaller than the sum of its proper divisors (39609589844388).

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

21101101112220 is a wasteful number, since it uses less digits than its factorization.

21101101112220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4819559 (or 4819557 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 21101101112220 its reverse (2221110110112), we get a palindrome (23322211222332).

The spelling of 21101101112220 in words is "twenty-one trillion, one hundred one billion, one hundred one million, one hundred twelve thousand, two hundred twenty".