21606530 has 32 divisors (see below), whose sum is σ = 42923520. Its totient is φ = 7765120.

The previous prime is 21606523. The next prime is 21606547. The reversal of 21606530 is 3560612.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21606496 and 21606505.

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, 8687 + ... + 10893.

It is an arithmetic number, because the mean of its divisors is an integer number (1341360).

Almost surely, 2^21606530 is an apocalyptic number.

21606530 is a deficient number, since it is larger than the sum of its proper divisors (21316990).

21606530 is a wasteful number, since it uses less digits than its factorization.

21606530 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2314.

The product of its (nonzero) digits is 1080, while the sum is 23.

The square root of 21606530 is about 4648.2824785075. The cubic root of 21606530 is about 278.5233916105.

The spelling of 21606530 in words is "twenty-one million, six hundred six thousand, five hundred thirty".