21260256 has 24 divisors (see below), whose sum is σ = 55808424. Its totient is φ = 7086720.

The previous prime is 21260233. The next prime is 21260273. The reversal of 21260256 is 65206212.

It is a tau number, because it is divible by the number of its divisors (24).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a zygodrome in base 11.

It is a congruent number.

It is an unprimeable number.

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, 110635 + ... + 110826.

It is an arithmetic number, because the mean of its divisors is an integer number (2325351).

Almost surely, 2^21260256 is an apocalyptic number.

It is an amenable number.

21260256 is an abundant number, since it is smaller than the sum of its proper divisors (34548168).

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

21260256 is a wasteful number, since it uses less digits than its factorization.

21260256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 221474 (or 221466 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 24.

The square root of 21260256 is about 4610.8845138433. The cubic root of 21260256 is about 277.0274662473.

Adding to 21260256 its reverse (65206212), we get a palindrome (86466468).

The spelling of 21260256 in words is "twenty-one million, two hundred sixty thousand, two hundred fifty-six".