21427271 has 2 divisors, whose sum is σ = 21427272. Its totient is φ = 21427270.

The previous prime is 21427247. The next prime is 21427309. The reversal of 21427271 is 17272412.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21427271 - 2¹⁰ = 21426247 is a prime.

It is a super-3 number, since 3×21427271³ (a number of 23 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21427271.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21427171) 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 as a sum of consecutive naturals, namely, 10713635 + 10713636.

It is an arithmetic number, because the mean of its divisors is an integer number (10713636).

Almost surely, 2^21427271 is an apocalyptic number.

21427271 is a deficient number, since it is larger than the sum of its proper divisors (1).

21427271 is an equidigital number, since it uses as much as digits as its factorization.

21427271 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1568, while the sum is 26.

The square root of 21427271 is about 4628.9600343922. The cubic root of 21427271 is about 277.7509933226.

Adding to 21427271 its reverse (17272412), we get a palindrome (38699683).

The spelling of 21427271 in words is "twenty-one million, four hundred twenty-seven thousand, two hundred seventy-one".