21103256 has 16 divisors (see below), whose sum is σ = 41896440. Its totient is φ = 9930880.

The previous prime is 21103253. The next prime is 21103267. The reversal of 21103256 is 65230112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21103253) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 77450 + ... + 77721.

Almost surely, 2^21103256 is an apocalyptic number.

It is an amenable number.

21103256 is a deficient number, since it is larger than the sum of its proper divisors (20793184).

21103256 is a wasteful number, since it uses less digits than its factorization.

21103256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155194 (or 155190 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 20.

The square root of 21103256 is about 4593.8280333508. The cubic root of 21103256 is about 276.3438618280.

Adding to 21103256 its reverse (65230112), we get a palindrome (86333368).

The spelling of 21103256 in words is "twenty-one million, one hundred three thousand, two hundred fifty-six".