21133271 has 4 divisors (see below), whose sum is σ = 21142632. Its totient is φ = 21123912.

The previous prime is 21133243. The next prime is 21133283. The reversal of 21133271 is 17233112.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21133271 - 2¹⁸ = 20871127 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 (21133241) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1025 + ... + 6581.

It is an arithmetic number, because the mean of its divisors is an integer number (5285658).

Almost surely, 2^21133271 is an apocalyptic number.

21133271 is a deficient number, since it is larger than the sum of its proper divisors (9361).

21133271 is an equidigital number, since it uses as much as digits as its factorization.

21133271 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9360.

The product of its digits is 252, while the sum is 20.

The square root of 21133271 is about 4597.0937558418. The cubic root of 21133271 is about 276.4748136858.

Adding to 21133271 its reverse (17233112), we get a palindrome (38366383).

The spelling of 21133271 in words is "twenty-one million, one hundred thirty-three thousand, two hundred seventy-one".