21118259 has 4 divisors (see below), whose sum is σ = 21174360. Its totient is φ = 21062160.

The previous prime is 21118249. The next prime is 21118277. The reversal of 21118259 is 95281112.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21118259 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 polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27482 + ... + 28239.

It is an arithmetic number, because the mean of its divisors is an integer number (5293590).

Almost surely, 2^21118259 is an apocalyptic number.

21118259 is a deficient number, since it is larger than the sum of its proper divisors (56101).

21118259 is an equidigital number, since it uses as much as digits as its factorization.

21118259 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56100.

The product of its digits is 1440, while the sum is 29.

The square root of 21118259 is about 4595.4606950773. The cubic root of 21118259 is about 276.4093336339.

The spelling of 21118259 in words is "twenty-one million, one hundred eighteen thousand, two hundred fifty-nine".