21268655 has 4 divisors (see below), whose sum is σ = 25522392. Its totient is φ = 17014920.

The previous prime is 21268631. The next prime is 21268661. The reversal of 21268655 is 55686212.

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

It is not a de Polignac number, because 21268655 - 2⁶ = 21268591 is a prime.

It is a Duffinian number.

It is a plaindrome in base 16.

It is a congruent number.

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, 2126861 + ... + 2126870.

It is an arithmetic number, because the mean of its divisors is an integer number (6380598).

Almost surely, 2^21268655 is an apocalyptic number.

21268655 is a deficient number, since it is larger than the sum of its proper divisors (4253737).

21268655 is an equidigital number, since it uses as much as digits as its factorization.

21268655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4253736.

The product of its digits is 28800, while the sum is 35.

The square root of 21268655 is about 4611.7952036056. The cubic root of 21268655 is about 277.0639419348.

The spelling of 21268655 in words is "twenty-one million, two hundred sixty-eight thousand, six hundred fifty-five".