21008085 has 32 divisors (see below), whose sum is σ = 40089600. Its totient is φ = 9185088.

The previous prime is 21008083. The next prime is 21008149. The reversal of 21008085 is 58080012.

It is not a de Polignac number, because 21008085 - 2¹ = 21008083 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21008081) 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 31 ways as a sum of consecutive naturals, for example, 1935 + ... + 6764.

It is an arithmetic number, because the mean of its divisors is an integer number (1252800).

Almost surely, 2^21008085 is an apocalyptic number.

It is an amenable number.

21008085 is a deficient number, since it is larger than the sum of its proper divisors (19081515).

21008085 is a wasteful number, since it uses less digits than its factorization.

21008085 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8737.

The product of its (nonzero) digits is 640, while the sum is 24.

The square root of 21008085 is about 4583.4577558869. The cubic root of 21008085 is about 275.9278192889.

Adding to 21008085 its reverse (58080012), we get a palindrome (79088097).

The spelling of 21008085 in words is "twenty-one million, eight thousand, eighty-five".