21101111221200 has 120 divisors (see below), whose sum is σ = 67622148655488. Its totient is φ = 5624610800640.

The previous prime is 21101111221133. The next prime is 21101111221243. The reversal of 21101111221200 is 212211110112.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (120).

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 21101111221200.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 802504 + ... + 6545703.

Almost surely, 2^{21101111221200} is an apocalyptic number.

21101111221200 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 21101111221200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33811074327744).

21101111221200 is an abundant number, since it is smaller than the sum of its proper divisors (46521037434288).

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

21101111221200 is a wasteful number, since it uses less digits than its factorization.

21101111221200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7350621 (or 7350610 counting only the distinct ones).

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

Adding to 21101111221200 its reverse (212211110112), we get a palindrome (21313322331312).

The spelling of 21101111221200 in words is "twenty-one trillion, one hundred one billion, one hundred eleven million, two hundred twenty-one thousand, two hundred".