195779977 has 2 divisors, whose sum is σ = 195779978. Its totient is φ = 195779976.

The previous prime is 195779929. The next prime is 195780017. The reversal of 195779977 is 779977591.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 178382736 + 17397241 = 13356^2 + 4171^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-195779977 is a prime.

It is not a weakly prime, because it can be changed into another prime (195779677) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 97889988 + 97889989.

It is an arithmetic number, because the mean of its divisors is an integer number (97889989).

Almost surely, 2^195779977 is an apocalyptic number.

It is an amenable number.

195779977 is a deficient number, since it is larger than the sum of its proper divisors (1).

195779977 is an equidigital number, since it uses as much as digits as its factorization.

195779977 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8751645, while the sum is 61.

The square root of 195779977 is about 13992.1398292041. The cubic root of 195779977 is about 580.6611337305.

The spelling of 195779977 in words is "one hundred ninety-five million, seven hundred seventy-nine thousand, nine hundred seventy-seven".