21120171 has 16 divisors (see below), whose sum is σ = 30326400. Its totient is φ = 13025408.

The previous prime is 21120163. The next prime is 21120179. The reversal of 21120171 is 17102112.

It is an interprime number because it is at equal distance from previous prime (21120163) and next prime (21120179).

It is a cyclic number.

It is not a de Polignac number, because 21120171 - 2³ = 21120163 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21120171.

It is not an unprimeable number, because it can be changed into a prime (21120179) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 501 + ... + 6518.

It is an arithmetic number, because the mean of its divisors is an integer number (1895400).

Almost surely, 2^21120171 is an apocalyptic number.

21120171 is a deficient number, since it is larger than the sum of its proper divisors (9206229).

21120171 is a wasteful number, since it uses less digits than its factorization.

21120171 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7098.

The product of its (nonzero) digits is 28, while the sum is 15.

The square root of 21120171 is about 4595.6687217422. The cubic root of 21120171 is about 276.4176752100.

Adding to 21120171 its reverse (17102112), we get a palindrome (38222283).

The spelling of 21120171 in words is "twenty-one million, one hundred twenty thousand, one hundred seventy-one".