99720197 has 2 divisors, whose sum is σ = 99720198. Its totient is φ = 99720196.

The previous prime is 99720193. The next prime is 99720221. The reversal of 99720197 is 79102799.

It is a Cunningham number, because it is equal to 9986²+1.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 99720196 + 1 = 9986^2 + 1^2 .

It is a cyclic number.

It is not a de Polignac number, because 99720197 - 2² = 99720193 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99720191) 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, 49860098 + 49860099.

It is an arithmetic number, because the mean of its divisors is an integer number (49860099).

Almost surely, 2^99720197 is an apocalyptic number.

It is an amenable number.

99720197 is a deficient number, since it is larger than the sum of its proper divisors (1).

99720197 is an equidigital number, since it uses as much as digits as its factorization.

99720197 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 71442, while the sum is 44.

The square root of 99720197 is about 9986.0000500701. Note that the first 4 decimals coincide. The cubic root of 99720197 is about 463.7255688071.

The spelling of 99720197 in words is "ninety-nine million, seven hundred twenty thousand, one hundred ninety-seven".