1816686181091 has 4 divisors (see below), whose sum is σ = 1860995600184. Its totient is φ = 1772376762000.

The previous prime is 1816686181061. The next prime is 1816686181099. The reversal of 1816686181091 is 1901816866181.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1816686181091 - 2²⁶ = 1816619072227 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1816686181099) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22154709485 + ... + 22154709566.

It is an arithmetic number, because the mean of its divisors is an integer number (465248900046).

Almost surely, 2^{1816686181091} is an apocalyptic number.

1816686181091 is a deficient number, since it is larger than the sum of its proper divisors (44309419093).

1816686181091 is an equidigital number, since it uses as much as digits as its factorization.

1816686181091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44309419092.

The product of its (nonzero) digits is 995328, while the sum is 56.

The spelling of 1816686181091 in words is "one trillion, eight hundred sixteen billion, six hundred eighty-six million, one hundred eighty-one thousand, ninety-one".