1667800165 has 4 divisors (see below), whose sum is σ = 2001360204. Its totient is φ = 1334240128.

The previous prime is 1667800157. The next prime is 1667800187. The reversal of 1667800165 is 5610087661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5610087661 = 947 ⋅5924063.

It can be written as a sum of positive squares in 2 ways, for example, as 239413729 + 1428386436 = 15473^2 + 37794^2 .

It is a cyclic number.

It is not a de Polignac number, because 1667800165 - 2³ = 1667800157 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 166780012 + ... + 166780021.

It is an arithmetic number, because the mean of its divisors is an integer number (500340051).

Almost surely, 2^1667800165 is an apocalyptic number.

It is an amenable number.

1667800165 is a deficient number, since it is larger than the sum of its proper divisors (333560039).

1667800165 is an equidigital number, since it uses as much as digits as its factorization.

1667800165 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333560038.

The product of its (nonzero) digits is 60480, while the sum is 40.

The square root of 1667800165 is about 40838.7091495312. The cubic root of 1667800165 is about 1185.8998227624.

The spelling of 1667800165 in words is "one billion, six hundred sixty-seven million, eight hundred thousand, one hundred sixty-five".