1686868857 has 6 divisors (see below), whose sum is σ = 2436588362. Its totient is φ = 1124579232.

The previous prime is 1686868817. The next prime is 1686868861. The reversal of 1686868857 is 7588686861.

It can be written as a sum of positive squares in only one way, i.e., 1500710121 + 186158736 = 38739^2 + 13644^2 .

It is not a de Polignac number, because 1686868857 - 2⁶ = 1686868793 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1686868794 and 1686868803.

It is not an unprimeable number, because it can be changed into a prime (1686868817) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 93714928 + ... + 93714945.

Almost surely, 2^1686868857 is an apocalyptic number.

It is an amenable number.

1686868857 is a deficient number, since it is larger than the sum of its proper divisors (749719505).

1686868857 is a wasteful number, since it uses less digits than its factorization.

1686868857 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 187429879 (or 187429876 counting only the distinct ones).

The product of its digits is 30965760, while the sum is 63.

The square root of 1686868857 is about 41071.5090665050. The cubic root of 1686868857 is about 1190.4023442365.

The spelling of 1686868857 in words is "one billion, six hundred eighty-six million, eight hundred sixty-eight thousand, eight hundred fifty-seven".