20328505 has 4 divisors (see below), whose sum is σ = 24394212. Its totient is φ = 16262800.

The previous prime is 20328479. The next prime is 20328533. The reversal of 20328505 is 50582302.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 50582302 = 2 ⋅25291151.

It can be written as a sum of positive squares in 2 ways, for example, as 15649936 + 4678569 = 3956^2 + 2163^2 .

It is a de Polignac number, because none of the positive numbers 2^k-20328505 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20328505.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2032846 + ... + 2032855.

It is an arithmetic number, because the mean of its divisors is an integer number (6098553).

Almost surely, 2^20328505 is an apocalyptic number.

It is an amenable number.

20328505 is a deficient number, since it is larger than the sum of its proper divisors (4065707).

20328505 is an equidigital number, since it uses as much as digits as its factorization.

20328505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4065706.

The product of its (nonzero) digits is 2400, while the sum is 25.

The square root of 20328505 is about 4508.7143400309. The cubic root of 20328505 is about 272.9198644874.

The spelling of 20328505 in words is "twenty million, three hundred twenty-eight thousand, five hundred five".