21070585 has 4 divisors (see below), whose sum is σ = 25284708. Its totient is φ = 16856464.

The previous prime is 21070583. The next prime is 21070589. The reversal of 21070585 is 58507012.

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 7112889 + 13957696 = 2667^2 + 3736^2 .

It is a cyclic number.

It is not a de Polignac number, because 21070585 - 2¹ = 21070583 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21070583) 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 3 ways as a sum of consecutive naturals, for example, 2107054 + ... + 2107063.

It is an arithmetic number, because the mean of its divisors is an integer number (6321177).

Almost surely, 2^21070585 is an apocalyptic number.

It is an amenable number.

21070585 is a deficient number, since it is larger than the sum of its proper divisors (4214123).

21070585 is an equidigital number, since it uses as much as digits as its factorization.

21070585 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4214122.

The product of its (nonzero) digits is 2800, while the sum is 28.

The square root of 21070585 is about 4590.2706891860. The cubic root of 21070585 is about 276.2011809475.

Adding to 21070585 its reverse (58507012), we get a palindrome (79577597).

The spelling of 21070585 in words is "twenty-one million, seventy thousand, five hundred eighty-five".