198978569 has 2 divisors, whose sum is σ = 198978570. Its totient is φ = 198978568.

The previous prime is 198978551. The next prime is 198978601. The reversal of 198978569 is 965879891.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 190798969 + 8179600 = 13813^2 + 2860^2 .

It is an emirp because it is prime and its reverse (965879891) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-198978569 is a prime.

It is a super-2 number, since 2×198978569² = 79184941842575522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (198978529) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99489284 + 99489285.

It is an arithmetic number, because the mean of its divisors is an integer number (99489285).

Almost surely, 2^198978569 is an apocalyptic number.

It is an amenable number.

198978569 is a deficient number, since it is larger than the sum of its proper divisors (1).

198978569 is an equidigital number, since it uses as much as digits as its factorization.

198978569 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9797760, while the sum is 62.

The square root of 198978569 is about 14105.9763575585. The cubic root of 198978569 is about 583.8062872022.

The spelling of 198978569 in words is "one hundred ninety-eight million, nine hundred seventy-eight thousand, five hundred sixty-nine".