21360256 has 32 divisors (see below), whose sum is σ = 44798400. Its totient is φ = 10116864.

The previous prime is 21360253. The next prime is 21360259. The reversal of 21360256 is 65206312.

It is an interprime number because it is at equal distance from previous prime (21360253) and next prime (21360259).

It is a tau number, because it is divible by the number of its divisors (32).

It is a self number, because there is not a number n which added to its sum of digits gives 21360256.

It is not an unprimeable number, because it can be changed into a prime (21360253) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1960 + ... + 6823.

It is an arithmetic number, because the mean of its divisors is an integer number (1399950).

Almost surely, 2^21360256 is an apocalyptic number.

It is an amenable number.

21360256 is an abundant number, since it is smaller than the sum of its proper divisors (23438144).

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

21360256 is an equidigital number, since it uses as much as digits as its factorization.

21360256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8816 (or 8804 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 25.

The square root of 21360256 is about 4621.7156987422. The cubic root of 21360256 is about 277.4611302861.

Adding to 21360256 its reverse (65206312), we get a palindrome (86566568).

The spelling of 21360256 in words is "twenty-one million, three hundred sixty thousand, two hundred fifty-six".