21118017 has 8 divisors (see below), whose sum is σ = 28619200. Its totient is φ = 13847760.

The previous prime is 21118007. The next prime is 21118021. The reversal of 21118017 is 71081112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21118017 - 2⁴ = 21118001 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21117984 and 21118002.

It is not an unprimeable number, because it can be changed into a prime (21118007) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 57517 + ... + 57882.

It is an arithmetic number, because the mean of its divisors is an integer number (3577400).

Almost surely, 2^21118017 is an apocalyptic number.

It is an amenable number.

21118017 is a deficient number, since it is larger than the sum of its proper divisors (7501183).

21118017 is a wasteful number, since it uses less digits than its factorization.

21118017 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 115463.

The product of its (nonzero) digits is 112, while the sum is 21.

The square root of 21118017 is about 4595.4343646711. The cubic root of 21118017 is about 276.4082778127.

Adding to 21118017 its reverse (71081112), we get a palindrome (92199129).

The spelling of 21118017 in words is "twenty-one million, one hundred eighteen thousand, seventeen".