21320352 has 72 divisors (see below), whose sum is σ = 61113780. Its totient is φ = 7050240.

The previous prime is 21320323. The next prime is 21320401. The reversal of 21320352 is 25302312.

It can be written as a sum of positive squares in 2 ways, for example, as 21123216 + 197136 = 4596^2 + 444^2 .

It is a tau number, because it is divible by the number of its divisors (72).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 51924 + ... + 52332.

Almost surely, 2^21320352 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21320352, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30556890).

21320352 is an abundant number, since it is smaller than the sum of its proper divisors (39793428).

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

21320352 is a wasteful number, since it uses less digits than its factorization.

21320352 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 606 (or 595 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 18.

The square root of 21320352 is about 4617.3966691199. The cubic root of 21320352 is about 277.2882436147.

Adding to 21320352 its reverse (25302312), we get a palindrome (46622664).

The spelling of 21320352 in words is "twenty-one million, three hundred twenty thousand, three hundred fifty-two".