21323100 has 144 divisors (see below), whose sum is σ = 67683168. Its totient is φ = 5160960.

The previous prime is 21323089. The next prime is 21323129. The reversal of 21323100 is 132312.

It is a happy number.

It is a super-2 number, since 2×21323100² = 909349187220000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 188644 + ... + 188756.

It is an arithmetic number, because the mean of its divisors is an integer number (470022).

Almost surely, 2^21323100 is an apocalyptic number.

21323100 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 21323100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33841584).

21323100 is an abundant number, since it is smaller than the sum of its proper divisors (46360068).

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

21323100 is a wasteful number, since it uses less digits than its factorization.

21323100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 184 (or 177 counting only the distinct ones).

The product of its (nonzero) digits is 36, while the sum is 12.

The square root of 21323100 is about 4617.6942298078. The cubic root of 21323100 is about 277.3001564161.

Adding to 21323100 its reverse (132312), we get a palindrome (21455412).

The spelling of 21323100 in words is "twenty-one million, three hundred twenty-three thousand, one hundred".