21982585 has 4 divisors (see below), whose sum is σ = 26379108. Its totient is φ = 17586064.

The previous prime is 21982579. The next prime is 21982603. The reversal of 21982585 is 58528912.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3415104 + 18567481 = 1848^2 + 4309^2 .

It is a cyclic number.

It is not a de Polignac number, because 21982585 - 2³ = 21982577 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2198254 + ... + 2198263.

It is an arithmetic number, because the mean of its divisors is an integer number (6594777).

Almost surely, 2^21982585 is an apocalyptic number.

It is an amenable number.

21982585 is a deficient number, since it is larger than the sum of its proper divisors (4396523).

21982585 is an equidigital number, since it uses as much as digits as its factorization.

21982585 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4396522.

The product of its digits is 57600, while the sum is 40.

The square root of 21982585 is about 4688.5589470540. The cubic root of 21982585 is about 280.1299779193.

The spelling of 21982585 in words is "twenty-one million, nine hundred eighty-two thousand, five hundred eighty-five".