1818072173 has 4 divisors (see below), whose sum is σ = 1822271388. Its totient is φ = 1813872960.

The previous prime is 1818072167. The next prime is 1818072187. The reversal of 1818072173 is 3712708181.

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 214710409 + 1603361764 = 14653^2 + 40042^2 .

It is a cyclic number.

It is not a de Polignac number, because 1818072173 - 2⁸ = 1818071917 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 (1818072073) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2098958 + ... + 2099823.

It is an arithmetic number, because the mean of its divisors is an integer number (455567847).

Almost surely, 2^1818072173 is an apocalyptic number.

It is an amenable number.

1818072173 is a deficient number, since it is larger than the sum of its proper divisors (4199215).

1818072173 is an equidigital number, since it uses as much as digits as its factorization.

1818072173 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4199214.

The product of its (nonzero) digits is 18816, while the sum is 38.

The square root of 1818072173 is about 42638.8575480160. The cubic root of 1818072173 is about 1220.4979095028.

The spelling of 1818072173 in words is "one billion, eight hundred eighteen million, seventy-two thousand, one hundred seventy-three".