21121111212200 has 288 divisors, whose sum is σ = 53376140181600. Its totient is φ = 7768546652160.

The previous prime is 21121111212181. The next prime is 21121111212209. The reversal of 21121111212200 is 221211112112.

It is a super-2 number, since 2×21121111212200² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is not an unprimeable number, because it can be changed into a prime (21121111212209) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 555843602 + ... + 555881598.

It is an arithmetic number, because the mean of its divisors is an integer number (185333820075).

Almost surely, 2^{21121111212200} is an apocalyptic number.

21121111212200 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 21121111212200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26688070090800).

21121111212200 is an abundant number, since it is smaller than the sum of its proper divisors (32255028969400).

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

21121111212200 is a wasteful number, since it uses less digits than its factorization.

21121111212200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38269 (or 38243 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 21121111212200 its reverse (221211112112), we get a palindrome (21342322324312).

The spelling of 21121111212200 in words is "twenty-one trillion, one hundred twenty-one billion, one hundred eleven million, two hundred twelve thousand, two hundred".