198132721 has 2 divisors, whose sum is σ = 198132722. Its totient is φ = 198132720.

The previous prime is 198132719. The next prime is 198132733. The reversal of 198132721 is 127231891.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 186022321 + 12110400 = 13639^2 + 3480^2 .

It is a cyclic number.

It is not a de Polignac number, because 198132721 - 2¹ = 198132719 is a prime.

It is a super-3 number, since 3×198132721³ (a number of 26 digits) contains 333 as substring.

Together with 198132719, it forms a pair of twin primes.

It is equal to p_10981159 and since 198132721 and 10981159 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (198132761) 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, 99066360 + 99066361.

It is an arithmetic number, because the mean of its divisors is an integer number (99066361).

Almost surely, 2^198132721 is an apocalyptic number.

It is an amenable number.

198132721 is a deficient number, since it is larger than the sum of its proper divisors (1).

198132721 is an equidigital number, since it uses as much as digits as its factorization.

198132721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6048, while the sum is 34.

The square root of 198132721 is about 14075.9625248151. The cubic root of 198132721 is about 582.9778684054.

The spelling of 198132721 in words is "one hundred ninety-eight million, one hundred thirty-two thousand, seven hundred twenty-one".