21116171 has 4 divisors (see below), whose sum is σ = 21325344. Its totient is φ = 20907000.

The previous prime is 21116119. The next prime is 21116191. The reversal of 21116171 is 17161112.

It is a happy number.

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

It is not a de Polignac number, because 21116171 - 2¹⁸ = 20854027 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21116191) 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, 104435 + ... + 104636.

It is an arithmetic number, because the mean of its divisors is an integer number (5331336).

Almost surely, 2^21116171 is an apocalyptic number.

21116171 is a deficient number, since it is larger than the sum of its proper divisors (209173).

21116171 is a wasteful number, since it uses less digits than its factorization.

21116171 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 209172.

The product of its digits is 84, while the sum is 20.

The square root of 21116171 is about 4595.2335087567. The cubic root of 21116171 is about 276.4002236387.

Adding to 21116171 its reverse (17161112), we get a palindrome (38277283).

The spelling of 21116171 in words is "twenty-one million, one hundred sixteen thousand, one hundred seventy-one".