21266655 has 8 divisors (see below), whose sum is σ = 34026672. Its totient is φ = 11342208.

The previous prime is 21266633. The next prime is 21266669. The reversal of 21266655 is 55666212.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21266655 - 2¹⁰ = 21265631 is a prime.

It is a super-2 number, since 2×21266655² = 904541229778050, which contains 22 as substring.

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 7 ways as a sum of consecutive naturals, for example, 708874 + ... + 708903.

It is an arithmetic number, because the mean of its divisors is an integer number (4253334).

Almost surely, 2^21266655 is an apocalyptic number.

21266655 is a deficient number, since it is larger than the sum of its proper divisors (12760017).

21266655 is a wasteful number, since it uses less digits than its factorization.

21266655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1417785.

The product of its digits is 21600, while the sum is 33.

The square root of 21266655 is about 4611.5783632071. The cubic root of 21266655 is about 277.0552570845.

The spelling of 21266655 in words is "twenty-one million, two hundred sixty-six thousand, six hundred fifty-five".