21118289 has 8 divisors (see below), whose sum is σ = 21671232. Its totient is φ = 20568240.

The previous prime is 21118277. The next prime is 21118303. The reversal of 21118289 is 98281112.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21118289 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21118219) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28052 + ... + 28794.

It is an arithmetic number, because the mean of its divisors is an integer number (2708904).

Almost surely, 2^21118289 is an apocalyptic number.

It is an amenable number.

21118289 is a deficient number, since it is larger than the sum of its proper divisors (552943).

21118289 is an equidigital number, since it uses as much as digits as its factorization.

21118289 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1447.

The product of its digits is 2304, while the sum is 32.

The square root of 21118289 is about 4595.4639591667. The cubic root of 21118289 is about 276.4094645202.

The spelling of 21118289 in words is "twenty-one million, one hundred eighteen thousand, two hundred eighty-nine".