18904805 has 4 divisors (see below), whose sum is σ = 22685772. Its totient is φ = 15123840.

The previous prime is 18904793. The next prime is 18904807. The reversal of 18904805 is 50840981.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 50840981 = 47 ⋅1081723.

It can be written as a sum of positive squares in 2 ways, for example, as 2896804 + 16008001 = 1702^2 + 4001^2 .

It is not a de Polignac number, because 18904805 - 2⁴ = 18904789 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 (18904807) 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, 1890476 + ... + 1890485.

It is an arithmetic number, because the mean of its divisors is an integer number (5671443).

Almost surely, 2^18904805 is an apocalyptic number.

It is an amenable number.

18904805 is a deficient number, since it is larger than the sum of its proper divisors (3780967).

18904805 is an equidigital number, since it uses as much as digits as its factorization.

18904805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3780966.

The product of its (nonzero) digits is 11520, while the sum is 35.

The square root of 18904805 is about 4347.9656162394. The cubic root of 18904805 is about 266.3937720425.

The spelling of 18904805 in words is "eighteen million, nine hundred four thousand, eight hundred five".