198199983997 has 4 divisors (see below), whose sum is σ = 198217602076. Its totient is φ = 198182365920.

The previous prime is 198199983871. The next prime is 198199984019. The reversal of 198199983997 is 799389991891.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 799389991891 = 352267 ⋅2269273.

It can be written as a sum of positive squares in 2 ways, for example, as 149649827716 + 48550156281 = 386846^2 + 220341^2 .

It is a cyclic number.

It is not a de Polignac number, because 198199983997 - 2²³ = 198191595389 is a prime.

It is a super-2 number, since 2×198199983997² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 198199983997.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (198199903997) 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, 8792154 + ... + 8814667.

It is an arithmetic number, because the mean of its divisors is an integer number (49554400519).

Almost surely, 2^198199983997 is an apocalyptic number.

It is an amenable number.

198199983997 is a deficient number, since it is larger than the sum of its proper divisors (17618079).

198199983997 is a wasteful number, since it uses less digits than its factorization.

198199983997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17618078.

The product of its digits is 714256704, while the sum is 82.

The spelling of 198199983997 in words is "one hundred ninety-eight billion, one hundred ninety-nine million, nine hundred eighty-three thousand, nine hundred ninety-seven".