21584985 has 32 divisors (see below), whose sum is σ = 37366272. Its totient is φ = 10598400.

The previous prime is 21584963. The next prime is 21584999. The reversal of 21584985 is 58948512.

It is a happy number.

It is not a de Polignac number, because 21584985 - 2⁹ = 21584473 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 11085 + ... + 12885.

It is an arithmetic number, because the mean of its divisors is an integer number (1167696).

Almost surely, 2^21584985 is an apocalyptic number.

It is an amenable number.

21584985 is a deficient number, since it is larger than the sum of its proper divisors (15781287).

21584985 is a wasteful number, since it uses less digits than its factorization.

21584985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1873.

The product of its digits is 115200, while the sum is 42.

The square root of 21584985 is about 4645.9643778230. The cubic root of 21584985 is about 278.4307840802.

The spelling of 21584985 in words is "twenty-one million, five hundred eighty-four thousand, nine hundred eighty-five".