20505189 has 16 divisors (see below), whose sum is σ = 28001600. Its totient is φ = 13343616.

The previous prime is 20505169. The next prime is 20505193. The reversal of 20505189 is 98150502.

It is not a de Polignac number, because 20505189 - 2⁵ = 20505157 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 (20505169) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23442 + ... + 24300.

It is an arithmetic number, because the mean of its divisors is an integer number (1750100).

Almost surely, 2^20505189 is an apocalyptic number.

It is an amenable number.

20505189 is a deficient number, since it is larger than the sum of its proper divisors (7496411).

20505189 is a wasteful number, since it uses less digits than its factorization.

20505189 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1044.

The product of its (nonzero) digits is 3600, while the sum is 30.

The square root of 20505189 is about 4528.2655620005. The cubic root of 20505189 is about 273.7082737011.

The spelling of 20505189 in words is "twenty million, five hundred five thousand, one hundred eighty-nine".