1668499993 has 2 divisors, whose sum is σ = 1668499994. Its totient is φ = 1668499992.

The previous prime is 1668499981. The next prime is 1668500033. The reversal of 1668499993 is 3999948661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1185906969 + 482593024 = 34437^2 + 21968^2 .

It is an emirp because it is prime and its reverse (3999948661) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1668499993 is a prime.

It is not a weakly prime, because it can be changed into another prime (1668499913) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 834249996 + 834249997.

It is an arithmetic number, because the mean of its divisors is an integer number (834249997).

Almost surely, 2^1668499993 is an apocalyptic number.

It is an amenable number.

1668499993 is a deficient number, since it is larger than the sum of its proper divisors (1).

1668499993 is an equidigital number, since it uses as much as digits as its factorization.

1668499993 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 22674816, while the sum is 64.

The square root of 1668499993 is about 40847.2764453152. The cubic root of 1668499993 is about 1186.0656719377.

The spelling of 1668499993 in words is "one billion, six hundred sixty-eight million, four hundred ninety-nine thousand, nine hundred ninety-three".