21123223221100 has 288 divisors, whose sum is σ = 62853373126656. Its totient is φ = 5948102937600.

The previous prime is 21123223221019. The next prime is 21123223221161. The reversal of 21123223221100 is 112232232112.

It is a Harshad number since it is a multiple of its sum of digits (22).

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 95 ways as a sum of consecutive naturals, for example, 2459794 + ... + 6949606.

It is an arithmetic number, because the mean of its divisors is an integer number (218240878912).

Almost surely, 2^{21123223221100} is an apocalyptic number.

21123223221100 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 21123223221100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31426686563328).

21123223221100 is an abundant number, since it is smaller than the sum of its proper divisors (41730149905556).

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

21123223221100 is a wasteful number, since it uses less digits than its factorization.

21123223221100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4489905 (or 4489898 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 22.

Adding to 21123223221100 its reverse (112232232112), we get a palindrome (21235455453212).

The spelling of 21123223221100 in words is "twenty-one trillion, one hundred twenty-three billion, two hundred twenty-three million, two hundred twenty-one thousand, one hundred".