21748266 has 12 divisors (see below), whose sum is σ = 47121282. Its totient is φ = 7249416.

The previous prime is 21748261. The next prime is 21748297. The reversal of 21748266 is 66284712.

It can be written as a sum of positive squares in only one way, i.e., 13505625 + 8242641 = 3675^2 + 2871^2 .

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21748266.

It is not an unprimeable number, because it can be changed into a prime (21748261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 604101 + ... + 604136.

Almost surely, 2^21748266 is an apocalyptic number.

21748266 is an abundant number, since it is smaller than the sum of its proper divisors (25373016).

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

21748266 is a wasteful number, since it uses less digits than its factorization.

21748266 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1208245 (or 1208242 counting only the distinct ones).

The product of its digits is 32256, while the sum is 36.

The square root of 21748266 is about 4663.5036185255. The cubic root of 21748266 is about 279.1310903601.

It can be divided in two parts, 2174 and 8266, that added together give a triangular number (10440 = T₁₄₄).

The spelling of 21748266 in words is "twenty-one million, seven hundred forty-eight thousand, two hundred sixty-six".