21440855 has 4 divisors (see below), whose sum is σ = 25729032. Its totient is φ = 17152680.

The previous prime is 21440851. The next prime is 21440863. The reversal of 21440855 is 55804412.

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

It is not a de Polignac number, because 21440855 - 2² = 21440851 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21440851) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2144081 + ... + 2144090.

It is an arithmetic number, because the mean of its divisors is an integer number (6432258).

Almost surely, 2^21440855 is an apocalyptic number.

21440855 is a deficient number, since it is larger than the sum of its proper divisors (4288177).

21440855 is an equidigital number, since it uses as much as digits as its factorization.

21440855 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4288176.

The product of its (nonzero) digits is 6400, while the sum is 29.

The square root of 21440855 is about 4630.4270861336. The cubic root of 21440855 is about 277.8096751223.

The spelling of 21440855 in words is "twenty-one million, four hundred forty thousand, eight hundred fifty-five".