166251380909 has 2 divisors, whose sum is σ = 166251380910. Its totient is φ = 166251380908.

The previous prime is 166251380899. The next prime is 166251380929. The reversal of 166251380909 is 909083152661.

It is a happy number.

166251380909 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 139261819684 + 26989561225 = 373178^2 + 164285^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-166251380909 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (166251380929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83125690454 + 83125690455.

It is an arithmetic number, because the mean of its divisors is an integer number (83125690455).

Almost surely, 2^166251380909 is an apocalyptic number.

It is an amenable number.

166251380909 is a deficient number, since it is larger than the sum of its proper divisors (1).

166251380909 is an equidigital number, since it uses as much as digits as its factorization.

166251380909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 699840, while the sum is 50.

The spelling of 166251380909 in words is "one hundred sixty-six billion, two hundred fifty-one million, three hundred eighty thousand, nine hundred nine".