21783268 has 12 divisors (see below), whose sum is σ = 41053180. Its totient is φ = 10053792.

The previous prime is 21783257. The next prime is 21783271. The reversal of 21783268 is 86238712.

It can be written as a sum of positive squares in 2 ways, for example, as 6666724 + 15116544 = 2582^2 + 3888^2 .

It is a hoax number, since the sum of its digits (37) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

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, 209403 + ... + 209506.

Almost surely, 2^21783268 is an apocalyptic number.

It is an amenable number.

21783268 is a deficient number, since it is larger than the sum of its proper divisors (19269912).

21783268 is a wasteful number, since it uses less digits than its factorization.

21783268 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 418926 (or 418924 counting only the distinct ones).

The product of its digits is 32256, while the sum is 37.

The square root of 21783268 is about 4667.2548676926. The cubic root of 21783268 is about 279.2807560806.

The spelling of 21783268 in words is "twenty-one million, seven hundred eighty-three thousand, two hundred sixty-eight".