21725271 has 12 divisors (see below), whose sum is σ = 32745648. Its totient is φ = 13853664.

The previous prime is 21725239. The next prime is 21725273. The reversal of 21725271 is 17252712.

It is not a de Polignac number, because 21725271 - 2⁵ = 21725239 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21725273) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 52270 + ... + 52683.

It is an arithmetic number, because the mean of its divisors is an integer number (2728804).

Almost surely, 2^21725271 is an apocalyptic number.

21725271 is a deficient number, since it is larger than the sum of its proper divisors (11020377).

21725271 is a wasteful number, since it uses less digits than its factorization.

21725271 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104982 (or 104979 counting only the distinct ones).

The product of its digits is 1960, while the sum is 27.

The square root of 21725271 is about 4661.0375454399. The cubic root of 21725271 is about 279.0326781780.

Adding to 21725271 its reverse (17252712), we get a palindrome (38977983).

The spelling of 21725271 in words is "twenty-one million, seven hundred twenty-five thousand, two hundred seventy-one".