21058530 has 16 divisors (see below), whose sum is σ = 50540544. Its totient is φ = 5615600.

The previous prime is 21058523. The next prime is 21058537. The reversal of 21058530 is 3585012.

It is an interprime number because it is at equal distance from previous prime (21058523) and next prime (21058537).

It is a self number, because there is not a number n which added to its sum of digits gives 21058530.

It is not an unprimeable number, because it can be changed into a prime (21058537) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 350946 + ... + 351005.

It is an arithmetic number, because the mean of its divisors is an integer number (3158784).

Almost surely, 2^21058530 is an apocalyptic number.

21058530 is an abundant number, since it is smaller than the sum of its proper divisors (29482014).

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

21058530 is a wasteful number, since it uses less digits than its factorization.

21058530 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 701961.

The product of its (nonzero) digits is 1200, while the sum is 24.

The square root of 21058530 is about 4588.9573979282. The cubic root of 21058530 is about 276.1484970690.

The spelling of 21058530 in words is "twenty-one million, fifty-eight thousand, five hundred thirty".