21085084 has 24 divisors (see below), whose sum is σ = 38503808. Its totient is φ = 10091520.

The previous prime is 21085061. The next prime is 21085087. The reversal of 21085084 is 48058012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21085087) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 11152 + ... + 12904.

Almost surely, 2^21085084 is an apocalyptic number.

It is an amenable number.

21085084 is a deficient number, since it is larger than the sum of its proper divisors (17418724).

21085084 is a wasteful number, since it uses less digits than its factorization.

21085084 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1885 (or 1883 counting only the distinct ones).

The product of its (nonzero) digits is 2560, while the sum is 28.

The square root of 21085084 is about 4591.8497362174. The cubic root of 21085084 is about 276.2645192099.

The spelling of 21085084 in words is "twenty-one million, eighty-five thousand, eighty-four".