1686140857 has 2 divisors, whose sum is σ = 1686140858. Its totient is φ = 1686140856.

The previous prime is 1686140849. The next prime is 1686140891. The reversal of 1686140857 is 7580416861.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1608330816 + 77810041 = 40104^2 + 8821^2 .

It is a cyclic number.

It is not a de Polignac number, because 1686140857 - 2³ = 1686140849 is a prime.

It is not a weakly prime, because it can be changed into another prime (1686140837) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 843070428 + 843070429.

It is an arithmetic number, because the mean of its divisors is an integer number (843070429).

Almost surely, 2^1686140857 is an apocalyptic number.

It is an amenable number.

1686140857 is a deficient number, since it is larger than the sum of its proper divisors (1).

1686140857 is an equidigital number, since it uses as much as digits as its factorization.

1686140857 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 322560, while the sum is 46.

The square root of 1686140857 is about 41062.6455187680. The cubic root of 1686140857 is about 1190.2310727512.

The spelling of 1686140857 in words is "one billion, six hundred eighty-six million, one hundred forty thousand, eight hundred fifty-seven".