21355271 has 8 divisors (see below), whose sum is σ = 24435360. Its totient is φ = 18282528.

The previous prime is 21355267. The next prime is 21355273. The reversal of 21355271 is 17255312.

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 21355271 - 2² = 21355267 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21355271.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21355273) 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 7 ways as a sum of consecutive naturals, for example, 7745 + ... + 10133.

It is an arithmetic number, because the mean of its divisors is an integer number (3054420).

Almost surely, 2^21355271 is an apocalyptic number.

21355271 is a deficient number, since it is larger than the sum of its proper divisors (3080089).

21355271 is a wasteful number, since it uses less digits than its factorization.

21355271 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3673.

The product of its digits is 2100, while the sum is 26.

The square root of 21355271 is about 4621.1763653858. The cubic root of 21355271 is about 277.4395442254.

The spelling of 21355271 in words is "twenty-one million, three hundred fifty-five thousand, two hundred seventy-one".