197979797 has 2 divisors, whose sum is σ = 197979798. Its totient is φ = 197979796.

The previous prime is 197979787. The next prime is 197979827. The reversal of 197979797 is 797979791.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 183033841 + 14945956 = 13529^2 + 3866^2 .

It is a cyclic number.

It is not a de Polignac number, because 197979797 - 2⁸ = 197979541 is a prime.

It is a super-2 number, since 2×197979797² = 78392000040322418, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (197979787) 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, 98989898 + 98989899.

It is an arithmetic number, because the mean of its divisors is an integer number (98989899).

Almost surely, 2^197979797 is an apocalyptic number.

It is an amenable number.

197979797 is a deficient number, since it is larger than the sum of its proper divisors (1).

197979797 is an equidigital number, since it uses as much as digits as its factorization.

197979797 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15752961, while the sum is 65.

The square root of 197979797 is about 14070.5293788116. The cubic root of 197979797 is about 582.8278439616.

The spelling of 197979797 in words is "one hundred ninety-seven million, nine hundred seventy-nine thousand, seven hundred ninety-seven".