21017118 has 8 divisors (see below), whose sum is σ = 42034248. Its totient is φ = 7005704.

The previous prime is 21017111. The next prime is 21017137. The reversal of 21017118 is 81171012.

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

21017118 is an admirable number.

It is a junction number, because it is equal to n+sod(n) for n = 21017094 and 21017103.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21017111) 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, 1751421 + ... + 1751432.

It is an arithmetic number, because the mean of its divisors is an integer number (5254281).

Almost surely, 2^21017118 is an apocalyptic number.

21017118 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21017118 is a wasteful number, since it uses less digits than its factorization.

21017118 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3502858.

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

The square root of 21017118 is about 4584.4430414174. The cubic root of 21017118 is about 275.9673611898.

The spelling of 21017118 in words is "twenty-one million, seventeen thousand, one hundred eighteen".