21111102011220 has 72 divisors (see below), whose sum is σ = 64007861986656. Its totient is φ = 5196578954112.

The previous prime is 21111102011213. The next prime is 21111102011267. The reversal of 21111102011220 is 2211020111112.

It is a happy number.

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 21111102011220.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1040971222 + ... + 1040991501.

It is an arithmetic number, because the mean of its divisors is an integer number (888998083148).

Almost surely, 2^{21111102011220} is an apocalyptic number.

21111102011220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21111102011220 is an abundant number, since it is smaller than the sum of its proper divisors (42896759975436).

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

21111102011220 is a wasteful number, since it uses less digits than its factorization.

21111102011220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2081962761 (or 2081962746 counting only the distinct ones).

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

Adding to 21111102011220 its reverse (2211020111112), we get a palindrome (23322122122332).

The spelling of 21111102011220 in words is "twenty-one trillion, one hundred eleven billion, one hundred two million, eleven thousand, two hundred twenty".