686128957 has 2 divisors, whose sum is σ = 686128958. Its totient is φ = 686128956.

The previous prime is 686128913. The next prime is 686128979. The reversal of 686128957 is 759821686.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 382358916 + 303770041 = 19554^2 + 17429^2 .

It is a cyclic number.

It is not a de Polignac number, because 686128957 - 2⁷ = 686128829 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (686128357) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343064478 + 343064479.

It is an arithmetic number, because the mean of its divisors is an integer number (343064479).

Almost surely, 2^686128957 is an apocalyptic number.

It is an amenable number.

686128957 is a deficient number, since it is larger than the sum of its proper divisors (1).

686128957 is an equidigital number, since it uses as much as digits as its factorization.

686128957 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1451520, while the sum is 52.

The square root of 686128957 is about 26194.0633923032. The cubic root of 686128957 is about 881.9999952866. Note that the first 5 decimals are identical.

The spelling of 686128957 in words is "six hundred eighty-six million, one hundred twenty-eight thousand, nine hundred fifty-seven".