21265655 has 8 divisors (see below), whose sum is σ = 26862000. Its totient is φ = 16117056.

The previous prime is 21265633. The next prime is 21265661. The reversal of 21265655 is 55656212.

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

It is a cyclic number.

It is not a de Polignac number, because 21265655 - 2⁸ = 21265399 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 111830 + ... + 112019.

It is an arithmetic number, because the mean of its divisors is an integer number (3357750).

Almost surely, 2^21265655 is an apocalyptic number.

21265655 is a deficient number, since it is larger than the sum of its proper divisors (5596345).

21265655 is a wasteful number, since it uses less digits than its factorization.

21265655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 223873.

The product of its digits is 18000, while the sum is 32.

The square root of 21265655 is about 4611.4699391843. The cubic root of 21265655 is about 277.0509144551.

It can be divided in two parts, 21 and 265655, that multiplied together give a palindrome (5578755).

The spelling of 21265655 in words is "twenty-one million, two hundred sixty-five thousand, six hundred fifty-five".