1865218865566 has 48 divisors (see below), whose sum is σ = 3519385298496. Its totient is φ = 736349558784.

The previous prime is 1865218865557. The next prime is 1865218865579. The reversal of 1865218865566 is 6655688125681.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 11832115 + ... + 11988718.

It is an arithmetic number, because the mean of its divisors is an integer number (73320527052).

Almost surely, 2^{1865218865566} is an apocalyptic number.

1865218865566 is a deficient number, since it is larger than the sum of its proper divisors (1654166432930).

1865218865566 is a wasteful number, since it uses less digits than its factorization.

1865218865566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23820913 (or 23820906 counting only the distinct ones).

The product of its digits is 165888000, while the sum is 67.

The spelling of 1865218865566 in words is "one trillion, eight hundred sixty-five billion, two hundred eighteen million, eight hundred sixty-five thousand, five hundred sixty-six".