21117589 has 4 divisors (see below), whose sum is σ = 21184524. Its totient is φ = 21050656.

The previous prime is 21117563. The next prime is 21117631. The reversal of 21117589 is 98571112.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 342225 + 20775364 = 585^2 + 4558^2 .

It is a cyclic number.

It is not a de Polignac number, because 21117589 - 2⁵ = 21117557 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21117559) 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 3 ways as a sum of consecutive naturals, for example, 32992 + ... + 33625.

It is an arithmetic number, because the mean of its divisors is an integer number (5296131).

Almost surely, 2^21117589 is an apocalyptic number.

It is an amenable number.

21117589 is a deficient number, since it is larger than the sum of its proper divisors (66935).

21117589 is an equidigital number, since it uses as much as digits as its factorization.

21117589 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66934.

The product of its digits is 5040, while the sum is 34.

The square root of 21117589 is about 4595.3877964759. The cubic root of 21117589 is about 276.4064104729.

The spelling of 21117589 in words is "twenty-one million, one hundred seventeen thousand, five hundred eighty-nine".