166681477 has 2 divisors, whose sum is σ = 166681478. Its totient is φ = 166681476.

The previous prime is 166681457. The next prime is 166681507. The reversal of 166681477 is 774186661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 136749636 + 29931841 = 11694^2 + 5471^2 .

It is an emirp because it is prime and its reverse (774186661) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-166681477 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (166681457) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83340738 + 83340739.

It is an arithmetic number, because the mean of its divisors is an integer number (83340739).

Almost surely, 2^166681477 is an apocalyptic number.

It is an amenable number.

166681477 is a deficient number, since it is larger than the sum of its proper divisors (1).

166681477 is an equidigital number, since it uses as much as digits as its factorization.

166681477 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 338688, while the sum is 46.

The square root of 166681477 is about 12910.5180763593. The cubic root of 166681477 is about 550.3375085474.

It can be divided in two parts, 16668 and 1477, that added together give a triangular number (18145 = T₁₉₀).

The spelling of 166681477 in words is "one hundred sixty-six million, six hundred eighty-one thousand, four hundred seventy-seven".