19890505 has 4 divisors (see below), whose sum is σ = 23868612. Its totient is φ = 15912400.

The previous prime is 19890503. The next prime is 19890509. The reversal of 19890505 is 50509891.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3697929 + 16192576 = 1923^2 + 4024^2 .

It is not a de Polignac number, because 19890505 - 2¹ = 19890503 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19890503) by changing a digit.

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, 1989046 + ... + 1989055.

It is an arithmetic number, because the mean of its divisors is an integer number (5967153).

Almost surely, 2^19890505 is an apocalyptic number.

It is an amenable number.

19890505 is a deficient number, since it is larger than the sum of its proper divisors (3978107).

19890505 is an equidigital number, since it uses as much as digits as its factorization.

19890505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3978106.

The product of its (nonzero) digits is 16200, while the sum is 37.

The square root of 19890505 is about 4459.8772404630. The cubic root of 19890505 is about 270.9454963169.

The spelling of 19890505 in words is "nineteen million, eight hundred ninety thousand, five hundred five".