166176721 has 2 divisors, whose sum is σ = 166176722. Its totient is φ = 166176720.

The previous prime is 166176697. The next prime is 166176727. The reversal of 166176721 is 127671661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 119596096 + 46580625 = 10936^2 + 6825^2 .

It is a cyclic number.

It is not a de Polignac number, because 166176721 - 2¹³ = 166168529 is a prime.

It is a super-2 number, since 2×166176721² = 55229405204623682, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (166176727) 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, 83088360 + 83088361.

It is an arithmetic number, because the mean of its divisors is an integer number (83088361).

Almost surely, 2^166176721 is an apocalyptic number.

It is an amenable number.

166176721 is a deficient number, since it is larger than the sum of its proper divisors (1).

166176721 is an equidigital number, since it uses as much as digits as its factorization.

166176721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 21168, while the sum is 37.

The square root of 166176721 is about 12890.9550072910. The cubic root of 166176721 is about 549.7814238907.

The spelling of 166176721 in words is "one hundred sixty-six million, one hundred seventy-six thousand, seven hundred twenty-one".