198849205981 has 4 divisors (see below), whose sum is σ = 198854866012. Its totient is φ = 198843545952.

The previous prime is 198849205957. The next prime is 198849205987. The reversal of 198849205981 is 189502948891.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 189502948891 = 197 ⋅961943903.

It can be written as a sum of positive squares in 2 ways, for example, as 123081688900 + 75767517081 = 350830^2 + 275259^2 .

It is a cyclic number.

It is not a de Polignac number, because 198849205981 - 2¹⁷ = 198849074909 is a prime.

It is a super-2 number, since 2×198849205981² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (198849205987) 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, 2776986 + ... + 2847691.

It is an arithmetic number, because the mean of its divisors is an integer number (49713716503).

Almost surely, 2^198849205981 is an apocalyptic number.

It is an amenable number.

198849205981 is a deficient number, since it is larger than the sum of its proper divisors (5660031).

198849205981 is an equidigital number, since it uses as much as digits as its factorization.

198849205981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5660030.

The product of its (nonzero) digits is 14929920, while the sum is 64.

The spelling of 198849205981 in words is "one hundred ninety-eight billion, eight hundred forty-nine million, two hundred five thousand, nine hundred eighty-one".