21530658 has 16 divisors (see below), whose sum is σ = 44112096. Its totient is φ = 7001760.

The previous prime is 21530627. The next prime is 21530669. The reversal of 21530658 is 85603512.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 43516 + ... + 44007.

It is an arithmetic number, because the mean of its divisors is an integer number (2757006).

Almost surely, 2^21530658 is an apocalyptic number.

21530658 is an abundant number, since it is smaller than the sum of its proper divisors (22581438).

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

21530658 is a wasteful number, since it uses less digits than its factorization.

21530658 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87569.

The product of its (nonzero) digits is 7200, while the sum is 30.

The square root of 21530658 is about 4640.1140072201. The cubic root of 21530658 is about 278.1969947526.

The spelling of 21530658 in words is "twenty-one million, five hundred thirty thousand, six hundred fifty-eight".