21152320 has 168 divisors, whose sum is σ = 62544960. Its totient is φ = 6773760.

The previous prime is 21152317. The next prime is 21152321. The reversal of 21152320 is 2325112.

It is a Harshad number since it is a multiple of its sum of digits (16).

It is a junction number, because it is equal to n+sod(n) for n = 21152294 and 21152303.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21152321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 297885 + ... + 297955.

Almost surely, 2^21152320 is an apocalyptic number.

21152320 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 21152320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31272480).

21152320 is an abundant number, since it is smaller than the sum of its proper divisors (41392640).

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

21152320 is a wasteful number, since it uses less digits than its factorization.

21152320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 121 (or 104 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 21152320 is about 4599.1651416317. The cubic root of 21152320 is about 276.5578578918.

Adding to 21152320 its reverse (2325112), we get a palindrome (23477432).

The spelling of 21152320 in words is "twenty-one million, one hundred fifty-two thousand, three hundred twenty".