21123200 has 192 divisors, whose sum is σ = 63745920. Its totient is φ = 6758400.

The previous prime is 21123187. The next prime is 21123211. The reversal of 21123200 is 232112.

It is a happy number.

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, 515180 + ... + 515220.

It is an arithmetic number, because the mean of its divisors is an integer number (332010).

Almost surely, 2^21123200 is an apocalyptic number.

21123200 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 21123200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31872960).

21123200 is an abundant number, since it is smaller than the sum of its proper divisors (42622720).

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

21123200 is a wasteful number, since it uses less digits than its factorization.

21123200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95 (or 78 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 11.

The square root of 21123200 is about 4595.9982593556. The cubic root of 21123200 is about 276.4308889464.

Adding to 21123200 its reverse (232112), we get a palindrome (21355312).

The spelling of 21123200 in words is "twenty-one million, one hundred twenty-three thousand, two hundred".