198440581 has 2 divisors, whose sum is σ = 198440582. Its totient is φ = 198440580.

The previous prime is 198440549. The next prime is 198440587. The reversal of 198440581 is 185044891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 170720356 + 27720225 = 13066^2 + 5265^2 .

It is an emirp because it is prime and its reverse (185044891) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 198440581 - 2⁵ = 198440549 is a prime.

It is a super-2 number, since 2×198440581² = 78757328375235122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (198440587) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99220290 + 99220291.

It is an arithmetic number, because the mean of its divisors is an integer number (99220291).

Almost surely, 2^198440581 is an apocalyptic number.

It is an amenable number.

198440581 is a deficient number, since it is larger than the sum of its proper divisors (1).

198440581 is an equidigital number, since it uses as much as digits as its factorization.

198440581 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 46080, while the sum is 40.

The square root of 198440581 is about 14086.8939443725. The cubic root of 198440581 is about 583.2796571745.

The spelling of 198440581 in words is "one hundred ninety-eight million, four hundred forty thousand, five hundred eighty-one".