21650256 has 60 divisors (see below), whose sum is σ = 60933600. Its totient is φ = 7176000.

The previous prime is 21650249. The next prime is 21650257. The reversal of 21650256 is 65205612.

21650256 = T₇₅ + T₇₆ + ... + T₅₀₆.

21650256 is a `hidden beast` number, since 2 + 1 + 650 + 2 + 5 + 6 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21650257) 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 11 ways as a sum of consecutive naturals, for example, 35845 + ... + 36443.

It is an arithmetic number, because the mean of its divisors is an integer number (1015560).

Almost surely, 2^21650256 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 21650256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30466800).

21650256 is an abundant number, since it is smaller than the sum of its proper divisors (39283344).

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

21650256 is a wasteful number, since it uses less digits than its factorization.

21650256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 864 (or 855 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 27.

The square root of 21650256 is about 4652.9835589652. The cubic root of 21650256 is about 278.7111513222.

Adding to 21650256 its reverse (65205612), we get a palindrome (86855868).

The spelling of 21650256 in words is "twenty-one million, six hundred fifty thousand, two hundred fifty-six".