1851981804067 has 4 divisors (see below), whose sum is σ = 1859023560240. Its totient is φ = 1844940047896.

The previous prime is 1851981804061. The next prime is 1851981804103. The reversal of 1851981804067 is 7604081891581.

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 1851981804067 - 2¹⁹ = 1851981279779 is a prime.

It is a Smith number, since the sum of its digits (58) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1851981804061) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 3520877692 + ... + 3520878217.

It is an arithmetic number, because the mean of its divisors is an integer number (464755890060).

Almost surely, 2^{1851981804067} is an apocalyptic number.

1851981804067 is a deficient number, since it is larger than the sum of its proper divisors (7041756173).

1851981804067 is an equidigital number, since it uses as much as digits as its factorization.

1851981804067 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7041756172.

The product of its (nonzero) digits is 3870720, while the sum is 58.

The spelling of 1851981804067 in words is "one trillion, eight hundred fifty-one billion, nine hundred eighty-one million, eight hundred four thousand, sixty-seven".