21711171 has 4 divisors (see below), whose sum is σ = 28948232. Its totient is φ = 14474112.

The previous prime is 21711163. The next prime is 21711229. The reversal of 21711171 is 17111712.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21711171 - 2³ = 21711163 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21711101) 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 3 ways as a sum of consecutive naturals, for example, 3618526 + ... + 3618531.

It is an arithmetic number, because the mean of its divisors is an integer number (7237058).

Almost surely, 2^21711171 is an apocalyptic number.

21711171 is a deficient number, since it is larger than the sum of its proper divisors (7237061).

21711171 is an equidigital number, since it uses as much as digits as its factorization.

21711171 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7237060.

The product of its digits is 98, while the sum is 21.

The square root of 21711171 is about 4659.5247611747. The cubic root of 21711171 is about 278.9722997640.

Adding to 21711171 its reverse (17111712), we get a palindrome (38822883).

The spelling of 21711171 in words is "twenty-one million, seven hundred eleven thousand, one hundred seventy-one".