21211256 has 16 divisors (see below), whose sum is σ = 43386840. Its totient is φ = 9641440.

The previous prime is 21211247. The next prime is 21211259. The reversal of 21211256 is 65211212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21211259) 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 3 ways as a sum of consecutive naturals, for example, 120431 + ... + 120606.

Almost surely, 2^21211256 is an apocalyptic number.

It is an amenable number.

21211256 is an abundant number, since it is smaller than the sum of its proper divisors (22175584).

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

21211256 is a wasteful number, since it uses less digits than its factorization.

21211256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 241054 (or 241050 counting only the distinct ones).

The product of its digits is 240, while the sum is 20.

The square root of 21211256 is about 4605.5679345766. The cubic root of 21211256 is about 276.8144743341.

Adding to 21211256 its reverse (65211212), we get a palindrome (86422468).

The spelling of 21211256 in words is "twenty-one million, two hundred eleven thousand, two hundred fifty-six".