21112520 has 64 divisors (see below), whose sum is σ = 55823040. Its totient is φ = 7084800.

The previous prime is 21112433. The next prime is 21112547. The reversal of 21112520 is 2521112.

It is a junction number, because it is equal to n+sod(n) for n = 21112495 and 21112504.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3875 + ... + 7565.

It is an arithmetic number, because the mean of its divisors is an integer number (872235).

Almost surely, 2^21112520 is an apocalyptic number.

21112520 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 21112520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27911520).

21112520 is an abundant number, since it is smaller than the sum of its proper divisors (34710520).

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

21112520 is a wasteful number, since it uses less digits than its factorization.

21112520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3726 (or 3722 counting only the distinct ones).

The product of its (nonzero) digits is 40, while the sum is 14.

The square root of 21112520 is about 4594.8362321197. The cubic root of 21112520 is about 276.3842927931.

Adding to 21112520 its reverse (2521112), we get a palindrome (23633632).

The spelling of 21112520 in words is "twenty-one million, one hundred twelve thousand, five hundred twenty".