21236000256 has 320 divisors, whose sum is σ = 66643948800. Its totient is φ = 6658080768.

The previous prime is 21236000251. The next prime is 21236000293. The reversal of 21236000256 is 65200063212.

21236000256 is a `hidden beast` number, since 2 + 1 + 2 + 3 + 600 + 0 + 2 + 56 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21236000251) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 61198675 + ... + 61199021.

It is an arithmetic number, because the mean of its divisors is an integer number (208262340).

Almost surely, 2^21236000256 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 21236000256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33321974400).

21236000256 is an abundant number, since it is smaller than the sum of its proper divisors (45407948544).

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

21236000256 is a wasteful number, since it uses less digits than its factorization.

21236000256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 626 (or 604 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 27.

Adding to 21236000256 its reverse (65200063212), we get a palindrome (86436063468).

The spelling of 21236000256 in words is "twenty-one billion, two hundred thirty-six million, two hundred fifty-six", and thus it is an aban number.