21170171 has 4 divisors (see below), whose sum is σ = 23094744. Its totient is φ = 19245600.

The previous prime is 21170159. The next prime is 21170207. The reversal of 21170171 is 17107112.

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

It is not a de Polignac number, because 21170171 - 2²² = 16975867 is a prime.

It is a super-2 number, since 2×21170171² = 896352280338482, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21170101) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 962270 + ... + 962291.

It is an arithmetic number, because the mean of its divisors is an integer number (5773686).

Almost surely, 2^21170171 is an apocalyptic number.

21170171 is a deficient number, since it is larger than the sum of its proper divisors (1924573).

21170171 is a wasteful number, since it uses less digits than its factorization.

21170171 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1924572.

The product of its (nonzero) digits is 98, while the sum is 20.

The square root of 21170171 is about 4601.1054106595. The cubic root of 21170171 is about 276.6356341704.

Adding to 21170171 its reverse (17107112), we get a palindrome (38277283).

The spelling of 21170171 in words is "twenty-one million, one hundred seventy thousand, one hundred seventy-one".