18890605 has 4 divisors (see below), whose sum is σ = 22668732. Its totient is φ = 15112480.

The previous prime is 18890603. The next prime is 18890611. The reversal of 18890605 is 50609881.

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 7941124 + 10949481 = 2818^2 + 3309^2 .

It is not a de Polignac number, because 18890605 - 2¹ = 18890603 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 (18890603) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1889056 + ... + 1889065.

It is an arithmetic number, because the mean of its divisors is an integer number (5667183).

Almost surely, 2^18890605 is an apocalyptic number.

It is an amenable number.

18890605 is a deficient number, since it is larger than the sum of its proper divisors (3778127).

18890605 is an equidigital number, since it uses as much as digits as its factorization.

18890605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3778126.

The product of its (nonzero) digits is 17280, while the sum is 37.

The square root of 18890605 is about 4346.3323618886. The cubic root of 18890605 is about 266.3270563921.

The spelling of 18890605 in words is "eighteen million, eight hundred ninety thousand, six hundred five".