18129805 has 4 divisors (see below), whose sum is σ = 21755772. Its totient is φ = 14503840.

The previous prime is 18129791. The next prime is 18129847. The reversal of 18129805 is 50892181.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 50892181 = 727 ⋅70003.

It can be written as a sum of positive squares in 2 ways, for example, as 10323369 + 7806436 = 3213^2 + 2794^2 .

It is not a de Polignac number, because 18129805 - 2¹¹ = 18127757 is a prime.

It is a Duffinian number.

It is a congruent number.

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, 1812976 + ... + 1812985.

It is an arithmetic number, because the mean of its divisors is an integer number (5438943).

Almost surely, 2^18129805 is an apocalyptic number.

It is an amenable number.

18129805 is a deficient number, since it is larger than the sum of its proper divisors (3625967).

18129805 is an equidigital number, since it uses as much as digits as its factorization.

18129805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3625966.

The product of its (nonzero) digits is 5760, while the sum is 34.

The square root of 18129805 is about 4257.9108727168. The cubic root of 18129805 is about 262.7026039781.

The spelling of 18129805 in words is "eighteen million, one hundred twenty-nine thousand, eight hundred five".