21789673 has 4 divisors (see below), whose sum is σ = 22114960. Its totient is φ = 21464388.

The previous prime is 21789661. The next prime is 21789679. The reversal of 21789673 is 37698712.

It is a happy number.

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 not a de Polignac number, because 21789673 - 2⁵ = 21789641 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21789679) 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, 162543 + ... + 162676.

It is an arithmetic number, because the mean of its divisors is an integer number (5528740).

Almost surely, 2^21789673 is an apocalyptic number.

It is an amenable number.

21789673 is a deficient number, since it is larger than the sum of its proper divisors (325287).

21789673 is an equidigital number, since it uses as much as digits as its factorization.

21789673 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 325286.

The product of its digits is 127008, while the sum is 43.

The square root of 21789673 is about 4667.9409807751. The cubic root of 21789673 is about 279.3081259859.

The spelling of 21789673 in words is "twenty-one million, seven hundred eighty-nine thousand, six hundred seventy-three".