21384789 has 8 divisors (see below), whose sum is σ = 28545792. Its totient is φ = 14240160.

The previous prime is 21384787. The next prime is 21384791. The reversal of 21384789 is 98748312.

It is an interprime number because it is at equal distance from previous prime (21384787) and next prime (21384791).

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

It is not a de Polignac number, because 21384789 - 2¹ = 21384787 is a prime.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a self number, because there is not a number n which added to its sum of digits gives 21384789.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21384787) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 624 + ... + 6569.

It is an arithmetic number, because the mean of its divisors is an integer number (3568224).

Almost surely, 2^21384789 is an apocalyptic number.

It is an amenable number.

21384789 is a deficient number, since it is larger than the sum of its proper divisors (7161003).

21384789 is an equidigital number, since it uses as much as digits as its factorization.

21384789 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8187.

The product of its digits is 96768, while the sum is 42.

The square root of 21384789 is about 4624.3690380418. The cubic root of 21384789 is about 277.5673142438.

The spelling of 21384789 in words is "twenty-one million, three hundred eighty-four thousand, seven hundred eighty-nine".