21268669 has 4 divisors (see below), whose sum is σ = 21278620. Its totient is φ = 21258720.

The previous prime is 21268661. The next prime is 21268679. The reversal of 21268669 is 96686212.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 9796900 + 11471769 = 3130^2 + 3387^2 .

It is a cyclic number.

It is not a de Polignac number, because 21268669 - 2³ = 21268661 is a prime.

It is a super-2 number, since 2×21268669² = 904712562063122, which contains 22 as substring.

It is a Duffinian number.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21268661) 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, 312 + ... + 6529.

It is an arithmetic number, because the mean of its divisors is an integer number (5319655).

Almost surely, 2^21268669 is an apocalyptic number.

It is an amenable number.

21268669 is a deficient number, since it is larger than the sum of its proper divisors (9951).

21268669 is an equidigital number, since it uses as much as digits as its factorization.

21268669 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9950.

The product of its digits is 62208, while the sum is 40.

The square root of 21268669 is about 4611.7967214525. The cubic root of 21268669 is about 277.0640027268.

The spelling of 21268669 in words is "twenty-one million, two hundred sixty-eight thousand, six hundred sixty-nine".