1668811687 has 2 divisors, whose sum is σ = 1668811688. Its totient is φ = 1668811686.

The previous prime is 1668811673. The next prime is 1668811693. The reversal of 1668811687 is 7861188661.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1668811687 - 2⁷ = 1668811559 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1668811087) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 834405843 + 834405844.

It is an arithmetic number, because the mean of its divisors is an integer number (834405844).

Almost surely, 2^1668811687 is an apocalyptic number.

1668811687 is a deficient number, since it is larger than the sum of its proper divisors (1).

1668811687 is an equidigital number, since it uses as much as digits as its factorization.

1668811687 is an evil number, because the sum of its binary digits is even.

The product of its digits is 774144, while the sum is 52.

The square root of 1668811687 is about 40851.0916255612. The cubic root of 1668811687 is about 1186.1395240078.

The spelling of 1668811687 in words is "one billion, six hundred sixty-eight million, eight hundred eleven thousand, six hundred eighty-seven".