21177271 has 2 divisors, whose sum is σ = 21177272. Its totient is φ = 21177270.

The previous prime is 21177269. The next prime is 21177281. The reversal of 21177271 is 17277112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21177271 - 2¹ = 21177269 is a prime.

Together with 21177269, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21177251) 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, 10588635 + 10588636.

It is an arithmetic number, because the mean of its divisors is an integer number (10588636).

Almost surely, 2^21177271 is an apocalyptic number.

21177271 is a deficient number, since it is larger than the sum of its proper divisors (1).

21177271 is an equidigital number, since it uses as much as digits as its factorization.

21177271 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1372, while the sum is 28.

The square root of 21177271 is about 4601.8768997008. The cubic root of 21177271 is about 276.6665565071. Note that the first 3 decimals are identical.

The spelling of 21177271 in words is "twenty-one million, one hundred seventy-seven thousand, two hundred seventy-one".