21000489 has 4 divisors (see below), whose sum is σ = 28000656. Its totient is φ = 14000324.

The previous prime is 21000481. The next prime is 21000509. The reversal of 21000489 is 98400012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21000489 - 2³ = 21000481 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21000481) 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, 3500079 + ... + 3500084.

It is an arithmetic number, because the mean of its divisors is an integer number (7000164).

Almost surely, 2^21000489 is an apocalyptic number.

It is an amenable number.

21000489 is a deficient number, since it is larger than the sum of its proper divisors (7000167).

21000489 is an equidigital number, since it uses as much as digits as its factorization.

21000489 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7000166.

The product of its (nonzero) digits is 576, while the sum is 24.

The square root of 21000489 is about 4582.6290489194. The cubic root of 21000489 is about 275.8945590722.

The spelling of 21000489 in words is "twenty-one million, four hundred eighty-nine", and thus it is an aban number.