21201320 has 96 divisors (see below), whose sum is σ = 57558600. Its totient is φ = 6999552.

The previous prime is 21201311. The next prime is 21201347. The reversal of 21201320 is 2310212.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 17522596 + 3678724 = 4186^2 + 1918^2 .

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, 56654 + ... + 57026.

Almost surely, 2^21201320 is an apocalyptic number.

21201320 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 21201320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28779300).

21201320 is an abundant number, since it is smaller than the sum of its proper divisors (36357280).

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

21201320 is a wasteful number, since it uses less digits than its factorization.

21201320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 427 (or 416 counting only the distinct ones).

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

The square root of 21201320 is about 4604.4891138974. The cubic root of 21201320 is about 276.7712447993.

Adding to 21201320 its reverse (2310212), we get a palindrome (23511532).

The spelling of 21201320 in words is "twenty-one million, two hundred one thousand, three hundred twenty".