166783993 has 2 divisors, whose sum is σ = 166783994. Its totient is φ = 166783992.

The previous prime is 166783987. The next prime is 166784011. The reversal of 166783993 is 399387661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 162511504 + 4272489 = 12748^2 + 2067^2 .

It is an emirp because it is prime and its reverse (399387661) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-166783993 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 166783993.

It is not a weakly prime, because it can be changed into another prime (166783093) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83391996 + 83391997.

It is an arithmetic number, because the mean of its divisors is an integer number (83391997).

Almost surely, 2^166783993 is an apocalyptic number.

It is an amenable number.

166783993 is a deficient number, since it is larger than the sum of its proper divisors (1).

166783993 is an equidigital number, since it uses as much as digits as its factorization.

166783993 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1469664, while the sum is 52.

The square root of 166783993 is about 12914.4877172887. The cubic root of 166783993 is about 550.4503121982.

The spelling of 166783993 in words is "one hundred sixty-six million, seven hundred eighty-three thousand, nine hundred ninety-three".