18520805 has 4 divisors (see below), whose sum is σ = 22224972. Its totient is φ = 14816640.

The previous prime is 18520793. The next prime is 18520829. The reversal of 18520805 is 50802581.

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 7873636 + 10647169 = 2806^2 + 3263^2 .

It is not a de Polignac number, because 18520805 - 2²⁴ = 1743589 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

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, 1852076 + ... + 1852085.

It is an arithmetic number, because the mean of its divisors is an integer number (5556243).

Almost surely, 2^18520805 is an apocalyptic number.

It is an amenable number.

18520805 is a deficient number, since it is larger than the sum of its proper divisors (3704167).

18520805 is an equidigital number, since it uses as much as digits as its factorization.

18520805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3704166.

The product of its (nonzero) digits is 3200, while the sum is 29.

The square root of 18520805 is about 4303.5804860604. The cubic root of 18520805 is about 264.5777302359.

It can be divided in two parts, 185 and 20805, that multiplied together give a triangular number (3848925 = T₂₇₇₄).

The spelling of 18520805 in words is "eighteen million, five hundred twenty thousand, eight hundred five".