21323120 has 160 divisors (see below), whose sum is σ = 63745920. Its totient is φ = 6451200.

The previous prime is 21323089. The next prime is 21323129. The reversal of 21323120 is 2132312.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (14).

It is a junction number, because it is equal to n+sod(n) for n = 21323095 and 21323104.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21323129) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 211070 + ... + 211170.

It is an arithmetic number, because the mean of its divisors is an integer number (398412).

Almost surely, 2^21323120 is an apocalyptic number.

21323120 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 21323120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31872960).

21323120 is an abundant number, since it is smaller than the sum of its proper divisors (42422800).

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

21323120 is a wasteful number, since it uses less digits than its factorization.

21323120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 163 (or 157 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 14.

The square root of 21323120 is about 4617.6963953902. The cubic root of 21323120 is about 277.3002431139.

Adding to 21323120 its reverse (2132312), we get a palindrome (23455432).

The spelling of 21323120 in words is "twenty-one million, three hundred twenty-three thousand, one hundred twenty".