198720101 has 2 divisors, whose sum is σ = 198720102. Its totient is φ = 198720100.

The previous prime is 198720097. The next prime is 198720103. The reversal of 198720101 is 101027891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 198669025 + 51076 = 14095^2 + 226^2 .

It is a cyclic number.

It is not a de Polignac number, because 198720101 - 2² = 198720097 is a prime.

It is a Sophie Germain prime.

Together with 198720103, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is equal to p_11011988 and since 198720101 and 11011988 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (198720103) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99360050 + 99360051.

It is an arithmetic number, because the mean of its divisors is an integer number (99360051).

Almost surely, 2^198720101 is an apocalyptic number.

It is an amenable number.

198720101 is a deficient number, since it is larger than the sum of its proper divisors (1).

198720101 is an equidigital number, since it uses as much as digits as its factorization.

198720101 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1008, while the sum is 29.

The square root of 198720101 is about 14096.8117317357. The cubic root of 198720101 is about 583.5533945955.

Adding to 198720101 its reverse (101027891), we get a palindrome (299747992).

The spelling of 198720101 in words is "one hundred ninety-eight million, seven hundred twenty thousand, one hundred one".