1998198181853 has 2 divisors, whose sum is σ = 1998198181854. Its totient is φ = 1998198181852.

The previous prime is 1998198181843. The next prime is 1998198181921. The reversal of 1998198181853 is 3581818918991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1998143392249 + 54789604 = 1413557^2 + 7402^2 .

It is an emirp because it is prime and its reverse (3581818918991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1998198181853 - 2¹² = 1998198177757 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1998198181843) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 999099090926 + 999099090927.

It is an arithmetic number, because the mean of its divisors is an integer number (999099090927).

Almost surely, 2^{1998198181853} is an apocalyptic number.

It is an amenable number.

1998198181853 is a deficient number, since it is larger than the sum of its proper divisors (1).

1998198181853 is an equidigital number, since it uses as much as digits as its factorization.

1998198181853 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 44789760, while the sum is 71.

The spelling of 1998198181853 in words is "one trillion, nine hundred ninety-eight billion, one hundred ninety-eight million, one hundred eighty-one thousand, eight hundred fifty-three".