21085044 has 12 divisors (see below), whose sum is σ = 49198464. Its totient is φ = 7028344.

The previous prime is 21085039. The next prime is 21085061. The reversal of 21085044 is 44058012.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

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 3 ways as a sum of consecutive naturals, for example, 878532 + ... + 878555.

It is an arithmetic number, because the mean of its divisors is an integer number (4099872).

Almost surely, 2^21085044 is an apocalyptic number.

It is an amenable number.

21085044 is an abundant number, since it is smaller than the sum of its proper divisors (28113420).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21085044 is a wasteful number, since it uses less digits than its factorization.

21085044 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1757094 (or 1757092 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 24.

The square root of 21085044 is about 4591.8453806721. The cubic root of 21085044 is about 276.2643445115.

The spelling of 21085044 in words is "twenty-one million, eighty-five thousand, forty-four".