1866835018681 has 4 divisors (see below), whose sum is σ = 1866855202164. Its totient is φ = 1866814835200.

The previous prime is 1866835018679. The next prime is 1866835018687. The reversal of 1866835018681 is 1868105386681.

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 223975027600 + 1642859991081 = 473260^2 + 1281741^2 .

It is a cyclic number.

It is not a de Polignac number, because 1866835018681 - 2¹ = 1866835018679 is a prime.

It is a super-2 number, since 2×1866835018681² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1866835018687) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9952360 + ... + 10138201.

It is an arithmetic number, because the mean of its divisors is an integer number (466713800541).

Almost surely, 2^{1866835018681} is an apocalyptic number.

It is an amenable number.

1866835018681 is a deficient number, since it is larger than the sum of its proper divisors (20183483).

1866835018681 is an equidigital number, since it uses as much as digits as its factorization.

1866835018681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20183482.

The product of its (nonzero) digits is 13271040, while the sum is 61.

The spelling of 1866835018681 in words is "one trillion, eight hundred sixty-six billion, eight hundred thirty-five million, eighteen thousand, six hundred eighty-one".