166801251779 has 2 divisors, whose sum is σ = 166801251780. Its totient is φ = 166801251778.

The previous prime is 166801251761. The next prime is 166801251803. The reversal of 166801251779 is 977152108661.

It is a weak prime.

It is an emirp because it is prime and its reverse (977152108661) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-166801251779 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 166801251779.

It is not a weakly prime, because it can be changed into another prime (166801251719) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83400625889 + 83400625890.

It is an arithmetic number, because the mean of its divisors is an integer number (83400625890).

Almost surely, 2^166801251779 is an apocalyptic number.

166801251779 is a deficient number, since it is larger than the sum of its proper divisors (1).

166801251779 is an equidigital number, since it uses as much as digits as its factorization.

166801251779 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1270080, while the sum is 53.

The spelling of 166801251779 in words is "one hundred sixty-six billion, eight hundred one million, two hundred fifty-one thousand, seven hundred seventy-nine".