21315056 has 20 divisors (see below), whose sum is σ = 47197872. Its totient is φ = 9134976.

The previous prime is 21315053. The next prime is 21315061. The reversal of 21315056 is 65051312.

It is a super-2 number, since 2×21315056² = 908663224566272, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21315053) 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 3 ways as a sum of consecutive naturals, for example, 95045 + ... + 95268.

Almost surely, 2^21315056 is an apocalyptic number.

It is an amenable number.

21315056 is an abundant number, since it is smaller than the sum of its proper divisors (25882816).

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

21315056 is a wasteful number, since it uses less digits than its factorization.

21315056 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 190328 (or 190322 counting only the distinct ones).

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

The square root of 21315056 is about 4616.8231501759. The cubic root of 21315056 is about 277.2652821403.

Adding to 21315056 its reverse (65051312), we get a palindrome (86366368).

The spelling of 21315056 in words is "twenty-one million, three hundred fifteen thousand, fifty-six".