166681818937 has 2 divisors, whose sum is σ = 166681818938. Its totient is φ = 166681818936.

The previous prime is 166681818931. The next prime is 166681818971. The reversal of 166681818937 is 739818186661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 162460588096 + 4221230841 = 403064^2 + 64971^2 .

It is an emirp because it is prime and its reverse (739818186661) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 166681818937 - 2³ = 166681818929 is a prime.

It is not a weakly prime, because it can be changed into another prime (166681818931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83340909468 + 83340909469.

It is an arithmetic number, because the mean of its divisors is an integer number (83340909469).

Almost surely, 2^166681818937 is an apocalyptic number.

It is an amenable number.

166681818937 is a deficient number, since it is larger than the sum of its proper divisors (1).

166681818937 is an equidigital number, since it uses as much as digits as its factorization.

166681818937 is an evil number, because the sum of its binary digits is even.

The product of its digits is 20901888, while the sum is 64.

The spelling of 166681818937 in words is "one hundred sixty-six billion, six hundred eighty-one million, eight hundred eighteen thousand, nine hundred thirty-seven".