1801981838197 has 4 divisors (see below), whose sum is σ = 1801984658656. Its totient is φ = 1801979017740.

The previous prime is 1801981838071. The next prime is 1801981838227. The reversal of 1801981838197 is 7918381891081.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1801981838197 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1801981835197) 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, 56872 + ... + 1899262.

It is an arithmetic number, because the mean of its divisors is an integer number (450496164664).

Almost surely, 2^{1801981838197} is an apocalyptic number.

It is an amenable number.

1801981838197 is a deficient number, since it is larger than the sum of its proper divisors (2820459).

1801981838197 is an equidigital number, since it uses as much as digits as its factorization.

1801981838197 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2820458.

The product of its (nonzero) digits is 6967296, while the sum is 64.

The spelling of 1801981838197 in words is "one trillion, eight hundred one billion, nine hundred eighty-one million, eight hundred thirty-eight thousand, one hundred ninety-seven".