21738585 has 16 divisors (see below), whose sum is σ = 37944000. Its totient is φ = 10539840.

The previous prime is 21738571. The next prime is 21738593. The reversal of 21738585 is 58583712.

It is not a de Polignac number, because 21738585 - 2⁸ = 21738329 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 65710 + ... + 66039.

It is an arithmetic number, because the mean of its divisors is an integer number (2371500).

Almost surely, 2^21738585 is an apocalyptic number.

It is an amenable number.

21738585 is a deficient number, since it is larger than the sum of its proper divisors (16205415).

21738585 is a wasteful number, since it uses less digits than its factorization.

21738585 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 131768.

The product of its digits is 67200, while the sum is 39.

The square root of 21738585 is about 4662.4655494706. The cubic root of 21738585 is about 279.0896668409.

It can be divided in two parts, 217385 and 85, that added together give a triangular number (217470 = T₆₅₉).

The spelling of 21738585 in words is "twenty-one million, seven hundred thirty-eight thousand, five hundred eighty-five".