21731271 has 8 divisors (see below), whose sum is σ = 29681904. Its totient is φ = 14134080.

The previous prime is 21731263. The next prime is 21731273. The reversal of 21731271 is 17213712.

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

It is not a de Polignac number, because 21731271 - 2³ = 21731263 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21731273) 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, 88216 + ... + 88461.

It is an arithmetic number, because the mean of its divisors is an integer number (3710238).

Almost surely, 2^21731271 is an apocalyptic number.

21731271 is a deficient number, since it is larger than the sum of its proper divisors (7950633).

21731271 is a wasteful number, since it uses less digits than its factorization.

21731271 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 176721.

The product of its digits is 588, while the sum is 24.

The square root of 21731271 is about 4661.6811345265. The cubic root of 21731271 is about 279.0583631966.

Adding to 21731271 its reverse (17213712), we get a palindrome (38944983).

The spelling of 21731271 in words is "twenty-one million, seven hundred thirty-one thousand, two hundred seventy-one".