21670171 has 4 divisors (see below), whose sum is σ = 21684472. Its totient is φ = 21655872.

The previous prime is 21670141. The next prime is 21670177. The reversal of 21670171 is 17107612.

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

It is a cyclic number.

It is not a de Polignac number, because 21670171 - 2¹¹ = 21668123 is a prime.

It is a super-2 number, since 2×21670171² = 939192622338482, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21670177) 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, 4566 + ... + 8011.

It is an arithmetic number, because the mean of its divisors is an integer number (5421118).

Almost surely, 2^21670171 is an apocalyptic number.

21670171 is a deficient number, since it is larger than the sum of its proper divisors (14301).

21670171 is a wasteful number, since it uses less digits than its factorization.

21670171 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14300.

The product of its (nonzero) digits is 588, while the sum is 25.

The square root of 21670171 is about 4655.1230918205. The cubic root of 21670171 is about 278.7965826686.

Adding to 21670171 its reverse (17107612), we get a palindrome (38777783).

The spelling of 21670171 in words is "twenty-one million, six hundred seventy thousand, one hundred seventy-one".