21671117 has 16 divisors (see below), whose sum is σ = 24167808. Its totient is φ = 19306560.

The previous prime is 21671101. The next prime is 21671123. The reversal of 21671117 is 71117612.

It is not a de Polignac number, because 21671117 - 2⁴ = 21671101 is a prime.

It is a Duffinian number.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21671137) 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 in 15 ways as a sum of consecutive naturals, for example, 48698 + ... + 49140.

It is an arithmetic number, because the mean of its divisors is an integer number (1510488).

Almost surely, 2^21671117 is an apocalyptic number.

It is an amenable number.

21671117 is a deficient number, since it is larger than the sum of its proper divisors (2496691).

21671117 is a wasteful number, since it uses less digits than its factorization.

21671117 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 580.

The product of its digits is 588, while the sum is 26.

The square root of 21671117 is about 4655.2246991955. The cubic root of 21671117 is about 278.8006395160.

Adding to 21671117 its reverse (71117612), we get a palindrome (92788729).

The spelling of 21671117 in words is "twenty-one million, six hundred seventy-one thousand, one hundred seventeen".