199961389 has 2 divisors, whose sum is σ = 199961390. Its totient is φ = 199961388.

The previous prime is 199961371. The next prime is 199961393. The reversal of 199961389 is 983169991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 165328164 + 34633225 = 12858^2 + 5885^2 .

It is a cyclic number.

It is not a de Polignac number, because 199961389 - 2⁷ = 199961261 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (199961189) 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, 99980694 + 99980695.

It is an arithmetic number, because the mean of its divisors is an integer number (99980695).

Almost surely, 2^199961389 is an apocalyptic number.

It is an amenable number.

199961389 is a deficient number, since it is larger than the sum of its proper divisors (1).

199961389 is an equidigital number, since it uses as much as digits as its factorization.

199961389 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 944784, while the sum is 55.

The square root of 199961389 is about 14140.7704528431. The cubic root of 199961389 is about 584.7659121376.

The spelling of 199961389 in words is "one hundred ninety-nine million, nine hundred sixty-one thousand, three hundred eighty-nine".