21855271 has 8 divisors (see below), whose sum is σ = 22733120. Its totient is φ = 20992608.

The previous prime is 21855259. The next prime is 21855277. The reversal of 21855271 is 17255812.

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 21855271 - 2⁷ = 21855143 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 (21855277) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 816 + ... + 6661.

It is an arithmetic number, because the mean of its divisors is an integer number (2841640).

Almost surely, 2^21855271 is an apocalyptic number.

21855271 is a deficient number, since it is larger than the sum of its proper divisors (877849).

21855271 is an equidigital number, since it uses as much as digits as its factorization.

21855271 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7593.

The product of its digits is 5600, while the sum is 31.

The square root of 21855271 is about 4674.9621388841. The cubic root of 21855271 is about 279.5881317009.

The spelling of 21855271 in words is "twenty-one million, eight hundred fifty-five thousand, two hundred seventy-one".