21085056 has 64 divisors (see below), whose sum is σ = 62240400. Its totient is φ = 7027200.

The previous prime is 21085039. The next prime is 21085061. The reversal of 21085056 is 65058012.

It is a tau number, because it is divible by the number of its divisors (64).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 406 + ... + 6506.

Almost surely, 2^21085056 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21085056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31120200).

21085056 is an abundant number, since it is smaller than the sum of its proper divisors (41155344).

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

21085056 is an equidigital number, since it uses as much as digits as its factorization.

21085056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6124 (or 6106 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 27.

The square root of 21085056 is about 4591.8466873362. The cubic root of 21085056 is about 276.2643969210.

The spelling of 21085056 in words is "twenty-one million, eighty-five thousand, fifty-six".