1686650857 has 2 divisors, whose sum is σ = 1686650858. Its totient is φ = 1686650856.

The previous prime is 1686650773. The next prime is 1686650863. The reversal of 1686650857 is 7580566861.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 879181801 + 807469056 = 29651^2 + 28416^2 .

It is a cyclic number.

It is not a de Polignac number, because 1686650857 - 2¹⁹ = 1686126569 is a prime.

It is a super-2 number, since 2×1686650857² = 5689582226837668898, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1686650057) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 843325428 + 843325429.

It is an arithmetic number, because the mean of its divisors is an integer number (843325429).

Almost surely, 2^1686650857 is an apocalyptic number.

It is an amenable number.

1686650857 is a deficient number, since it is larger than the sum of its proper divisors (1).

1686650857 is an equidigital number, since it uses as much as digits as its factorization.

1686650857 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2419200, while the sum is 52.

The square root of 1686650857 is about 41068.8550729138. The cubic root of 1686650857 is about 1190.3510620657.

The spelling of 1686650857 in words is "one billion, six hundred eighty-six million, six hundred fifty thousand, eight hundred fifty-seven".