1668686703637 has 2 divisors, whose sum is σ = 1668686703638. Its totient is φ = 1668686703636.

The previous prime is 1668686703617. The next prime is 1668686703667. The reversal of 1668686703637 is 7363076868661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1134280380676 + 534406322961 = 1065026^2 + 731031^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1668686703637 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1668686703617) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 834343351818 + 834343351819.

It is an arithmetic number, because the mean of its divisors is an integer number (834343351819).

Almost surely, 2^{1668686703637} is an apocalyptic number.

It is an amenable number.

1668686703637 is a deficient number, since it is larger than the sum of its proper divisors (1).

1668686703637 is an equidigital number, since it uses as much as digits as its factorization.

1668686703637 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 219469824, while the sum is 67.

The spelling of 1668686703637 in words is "one trillion, six hundred sixty-eight billion, six hundred eighty-six million, seven hundred three thousand, six hundred thirty-seven".