21423266 has 4 divisors (see below), whose sum is σ = 32134902. Its totient is φ = 10711632.

The previous prime is 21423251. The next prime is 21423271. The reversal of 21423266 is 66232412.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 19404025 + 2019241 = 4405^2 + 1421^2 .

It is a super-3 number, since 3×21423266³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

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 as a sum of consecutive naturals, namely, 5355815 + ... + 5355818.

Almost surely, 2^21423266 is an apocalyptic number.

21423266 is a deficient number, since it is larger than the sum of its proper divisors (10711636).

21423266 is a wasteful number, since it uses less digits than its factorization.

21423266 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10711635.

The product of its digits is 3456, while the sum is 26.

The square root of 21423266 is about 4628.5274116073. The cubic root of 21423266 is about 277.7336873073.

Adding to 21423266 its reverse (66232412), we get a palindrome (87655678).

The spelling of 21423266 in words is "twenty-one million, four hundred twenty-three thousand, two hundred sixty-six".