1680871649 has 2 divisors, whose sum is σ = 1680871650. Its totient is φ = 1680871648.

The previous prime is 1680871541. The next prime is 1680871663. The reversal of 1680871649 is 9461780861.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1653235600 + 27636049 = 40660^2 + 5257^2 .

It is a cyclic number.

It is not a de Polignac number, because 1680871649 - 2⁸ = 1680871393 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1680871597 and 1680871606.

It is not a weakly prime, because it can be changed into another prime (1680871249) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 840435824 + 840435825.

It is an arithmetic number, because the mean of its divisors is an integer number (840435825).

Almost surely, 2^1680871649 is an apocalyptic number.

It is an amenable number.

1680871649 is a deficient number, since it is larger than the sum of its proper divisors (1).

1680871649 is an equidigital number, since it uses as much as digits as its factorization.

1680871649 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 580608, while the sum is 50.

The square root of 1680871649 is about 40998.4347140229. The cubic root of 1680871649 is about 1188.9899507847.

The spelling of 1680871649 in words is "one billion, six hundred eighty million, eight hundred seventy-one thousand, six hundred forty-nine".