20985173 has 4 divisors (see below), whose sum is σ = 22892928. Its totient is φ = 19077420.

The previous prime is 20985169. The next prime is 20985187. The reversal of 20985173 is 37158902.

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 20985173 - 2² = 20985169 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20985113) 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, 953861 + ... + 953882.

It is an arithmetic number, because the mean of its divisors is an integer number (5723232).

Almost surely, 2^20985173 is an apocalyptic number.

It is an amenable number.

20985173 is a deficient number, since it is larger than the sum of its proper divisors (1907755).

20985173 is a wasteful number, since it uses less digits than its factorization.

20985173 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1907754.

The product of its (nonzero) digits is 15120, while the sum is 35.

The square root of 20985173 is about 4580.9576509721. The cubic root of 20985173 is about 275.8274712891.

The spelling of 20985173 in words is "twenty million, nine hundred eighty-five thousand, one hundred seventy-three".