21200256 has 192 divisors, whose sum is σ = 76377600. Its totient is φ = 5483520.

The previous prime is 21200233. The next prime is 21200279. The reversal of 21200256 is 65200212.

It is an interprime number because it is at equal distance from previous prime (21200233) and next prime (21200279).

It is a tau number, because it is divible by the number of its divisors (192).

It is a Harshad number since it is a multiple of its sum of digits (18).

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 23 ways as a sum of consecutive naturals, for example, 88585 + ... + 88823.

It is an arithmetic number, because the mean of its divisors is an integer number (397800).

Almost surely, 2^21200256 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21200256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38188800).

21200256 is an abundant number, since it is smaller than the sum of its proper divisors (55177344).

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

21200256 is a wasteful number, since it uses less digits than its factorization.

21200256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 277 (or 262 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 21200256 is about 4604.3735730281. The cubic root of 21200256 is about 276.7666147491.

Adding to 21200256 its reverse (65200212), we get a palindrome (86400468).

The spelling of 21200256 in words is "twenty-one million, two hundred thousand, two hundred fifty-six".