20665873 has 4 divisors (see below), whose sum is σ = 20859120. Its totient is φ = 20472628.

The previous prime is 20665867. The next prime is 20665907. The reversal of 20665873 is 37856602.

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 20665873 - 2⁹ = 20665361 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20665273) 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, 96463 + ... + 96676.

It is an arithmetic number, because the mean of its divisors is an integer number (5214780).

Almost surely, 2^20665873 is an apocalyptic number.

It is an amenable number.

20665873 is a deficient number, since it is larger than the sum of its proper divisors (193247).

20665873 is a wasteful number, since it uses less digits than its factorization.

20665873 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 193246.

The product of its (nonzero) digits is 60480, while the sum is 37.

The square root of 20665873 is about 4545.9732731286. The cubic root of 20665873 is about 274.4213640445.

The spelling of 20665873 in words is "twenty million, six hundred sixty-five thousand, eight hundred seventy-three".