21052830 has 16 divisors (see below), whose sum is σ = 50526864. Its totient is φ = 5614080.

The previous prime is 21052771. The next prime is 21052841. The reversal of 21052830 is 3825012.

It is a junction number, because it is equal to n+sod(n) for n = 21052797 and 21052806.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 350851 + ... + 350910.

It is an arithmetic number, because the mean of its divisors is an integer number (3157929).

Almost surely, 2^21052830 is an apocalyptic number.

21052830 is an abundant number, since it is smaller than the sum of its proper divisors (29474034).

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

21052830 is a wasteful number, since it uses less digits than its factorization.

21052830 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 701771.

The product of its (nonzero) digits is 480, while the sum is 21.

The square root of 21052830 is about 4588.3362997932. The cubic root of 21052830 is about 276.1235793995.

Adding to 21052830 its reverse (3825012), we get a palindrome (24877842).

The spelling of 21052830 in words is "twenty-one million, fifty-two thousand, eight hundred thirty".