21052680 has 128 divisors (see below), whose sum is σ = 70761600. Its totient is φ = 4966400.

The previous prime is 21052679. The next prime is 21052687. The reversal of 21052680 is 8625012.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 21052680.

It is not an unprimeable number, because it can be changed into a prime (21052687) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 53926 + ... + 54314.

It is an arithmetic number, because the mean of its divisors is an integer number (552825).

Almost surely, 2^21052680 is an apocalyptic number.

21052680 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 21052680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35380800).

21052680 is an abundant number, since it is smaller than the sum of its proper divisors (49708920).

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

21052680 is a wasteful number, since it uses less digits than its factorization.

21052680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 455 (or 451 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 24.

The square root of 21052680 is about 4588.3199539701. The cubic root of 21052680 is about 276.1229236106.

Adding to 21052680 its reverse (8625012), we get a palindrome (29677692).

The spelling of 21052680 in words is "twenty-one million, fifty-two thousand, six hundred eighty".