198921959 has 2 divisors, whose sum is σ = 198921960. Its totient is φ = 198921958.

The previous prime is 198921911. The next prime is 198921971. The reversal of 198921959 is 959129891.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 198921959 - 2⁸ = 198921703 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 198921959.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (198921979) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99460979 + 99460980.

It is an arithmetic number, because the mean of its divisors is an integer number (99460980).

Almost surely, 2^198921959 is an apocalyptic number.

198921959 is a deficient number, since it is larger than the sum of its proper divisors (1).

198921959 is an equidigital number, since it uses as much as digits as its factorization.

198921959 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 524880, while the sum is 53.

The square root of 198921959 is about 14103.9696185152. The cubic root of 198921959 is about 583.7509170706.

The spelling of 198921959 in words is "one hundred ninety-eight million, nine hundred twenty-one thousand, nine hundred fifty-nine".