21226756 has 6 divisors (see below), whose sum is σ = 37146830. Its totient is φ = 10613376.

The previous prime is 21226741. The next prime is 21226757. The reversal of 21226756 is 65762212.

It can be written as a sum of positive squares in only one way, i.e., 11088900 + 10137856 = 3330^2 + 3184^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21226757) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2653341 + ... + 2653348.

Almost surely, 2^21226756 is an apocalyptic number.

It is an amenable number.

21226756 is a deficient number, since it is larger than the sum of its proper divisors (15920074).

21226756 is a wasteful number, since it uses less digits than its factorization.

21226756 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5306693 (or 5306691 counting only the distinct ones).

The product of its digits is 10080, while the sum is 31.

The square root of 21226756 is about 4607.2503730533. The cubic root of 21226756 is about 276.8818847641.

Adding to 21226756 its reverse (65762212), we get a palindrome (86988968).

The spelling of 21226756 in words is "twenty-one million, two hundred twenty-six thousand, seven hundred fifty-six".