21135056 has 20 divisors (see below), whose sum is σ = 42271104. Its totient is φ = 10226400.

The previous prime is 21135053. The next prime is 21135071. The reversal of 21135056 is 65053112.

21135056 is an admirable number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21135053) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20810 + ... + 21801.

Almost surely, 2^21135056 is an apocalyptic number.

It is an amenable number.

21135056 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21135056 is a wasteful number, since it uses less digits than its factorization.

21135056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42650 (or 42644 counting only the distinct ones).

The product of its (nonzero) digits is 900, while the sum is 23.

The square root of 21135056 is about 4597.2878961405. The cubic root of 21135056 is about 276.4825975202.

Adding to 21135056 its reverse (65053112), we get a palindrome (86188168).

The spelling of 21135056 in words is "twenty-one million, one hundred thirty-five thousand, fifty-six".