21125585 has 8 divisors (see below), whose sum is σ = 27300840. Its totient is φ = 15600384.

The previous prime is 21125551. The next prime is 21125603. The reversal of 21125585 is 58552112.

It can be written as a sum of positive squares in 4 ways, for example, as 368449 + 20757136 = 607^2 + 4556^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21125585 - 2⁶ = 21125521 is a prime.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 162440 + ... + 162569.

It is an arithmetic number, because the mean of its divisors is an integer number (3412605).

Almost surely, 2^21125585 is an apocalyptic number.

It is an amenable number.

21125585 is a deficient number, since it is larger than the sum of its proper divisors (6175255).

21125585 is a wasteful number, since it uses less digits than its factorization.

21125585 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 325027.

The product of its digits is 4000, while the sum is 29.

The square root of 21125585 is about 4596.2577168823. The cubic root of 21125585 is about 276.4412924026.

Adding to 21125585 its reverse (58552112), we get a palindrome (79677697).

The spelling of 21125585 in words is "twenty-one million, one hundred twenty-five thousand, five hundred eighty-five".