686177977 has 2 divisors, whose sum is σ = 686177978. Its totient is φ = 686177976.

The previous prime is 686177971. The next prime is 686177993. The reversal of 686177977 is 779771686.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 364657216 + 321520761 = 19096^2 + 17931^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-686177977 is a prime.

It is a super-2 number, since 2×686177977² = 941680432239625058, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (686177971) 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, 343088988 + 343088989.

It is an arithmetic number, because the mean of its divisors is an integer number (343088989).

Almost surely, 2^686177977 is an apocalyptic number.

It is an amenable number.

686177977 is a deficient number, since it is larger than the sum of its proper divisors (1).

686177977 is an equidigital number, since it uses as much as digits as its factorization.

686177977 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6223392, while the sum is 58.

The square root of 686177977 is about 26194.9990837946. Note that the first 3 decimals coincide. The cubic root of 686177977 is about 882.0209994092.

The spelling of 686177977 in words is "six hundred eighty-six million, one hundred seventy-seven thousand, nine hundred seventy-seven".