21075289 has 8 divisors (see below), whose sum is σ = 21811680. Its totient is φ = 20350176.

The previous prime is 21075283. The next prime is 21075347. The reversal of 21075289 is 98257012.

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

It is a cyclic number.

It is not a de Polignac number, because 21075289 - 2¹⁹ = 20551001 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21075283) 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, 1074 + ... + 6580.

It is an arithmetic number, because the mean of its divisors is an integer number (2726460).

Almost surely, 2^21075289 is an apocalyptic number.

It is an amenable number.

21075289 is a deficient number, since it is larger than the sum of its proper divisors (736391).

21075289 is an equidigital number, since it uses as much as digits as its factorization.

21075289 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5639.

The product of its (nonzero) digits is 10080, while the sum is 34.

The square root of 21075289 is about 4590.7830486748. The cubic root of 21075289 is about 276.2217333540.

It can be divided in two parts, 2107 and 5289, that added together give a square (7396 = 86²).

The spelling of 21075289 in words is "twenty-one million, seventy-five thousand, two hundred eighty-nine".