21585056 has 12 divisors (see below), whose sum is σ = 42495642. Its totient is φ = 10792512.

The previous prime is 21585041. The next prime is 21585059. The reversal of 21585056 is 65058512.

It can be written as a sum of positive squares in only one way, i.e., 15335056 + 6250000 = 3916^2 + 2500^2 .

It is a Harshad number since it is a multiple of its sum of digits (32), and also a Moran number because the ratio is a prime number: 674533 = 21585056 / (2 + 1 + 5 + 8 + 5 + 0 + 5 + 6).

It is not an unprimeable number, because it can be changed into a prime (21585059) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 337235 + ... + 337298.

Almost surely, 2^21585056 is an apocalyptic number.

It is an amenable number.

21585056 is a deficient number, since it is larger than the sum of its proper divisors (20910586).

21585056 is an equidigital number, since it uses as much as digits as its factorization.

21585056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 674543 (or 674535 counting only the distinct ones).

The product of its (nonzero) digits is 12000, while the sum is 32.

The square root of 21585056 is about 4645.9720188568. The cubic root of 21585056 is about 278.4310893629.

The spelling of 21585056 in words is "twenty-one million, five hundred eighty-five thousand, fifty-six".