21113320 has 64 divisors (see below), whose sum is σ = 51224400. Its totient is φ = 7802880.

The previous prime is 21113317. The next prime is 21113329. The reversal of 21113320 is 2331112.

It can be written as a sum of positive squares in 8 ways, for example, as 9375844 + 11737476 = 3062^2 + 3426^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21113320.

It is not an unprimeable number, because it can be changed into a prime (21113329) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 41226 + ... + 41734.

Almost surely, 2^21113320 is an apocalyptic number.

21113320 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 21113320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25612200).

21113320 is an abundant number, since it is smaller than the sum of its proper divisors (30111080).

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

21113320 is a wasteful number, since it uses less digits than its factorization.

21113320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 598 (or 594 counting only the distinct ones).

The product of its (nonzero) digits is 36, while the sum is 13.

The square root of 21113320 is about 4594.9232855402. The cubic root of 21113320 is about 276.3877836860.

Adding to 21113320 its reverse (2331112), we get a palindrome (23444432).

It can be divided in two parts, 211 and 13320, that added together give a palindrome (13531).

The spelling of 21113320 in words is "twenty-one million, one hundred thirteen thousand, three hundred twenty".