167665681 has 2 divisors, whose sum is σ = 167665682. Its totient is φ = 167665680.

The previous prime is 167665661. The next prime is 167665697. The reversal of 167665681 is 186566761.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 150896656 + 16769025 = 12284^2 + 4095^2 .

It is an emirp because it is prime and its reverse (186566761) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 167665681 - 2¹⁹ = 167141393 is a prime.

It is a super-2 number, since 2×167665681² = 56223561170387522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (167665651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83832840 + 83832841.

It is an arithmetic number, because the mean of its divisors is an integer number (83832841).

Almost surely, 2^167665681 is an apocalyptic number.

It is an amenable number.

167665681 is a deficient number, since it is larger than the sum of its proper divisors (1).

167665681 is an equidigital number, since it uses as much as digits as its factorization.

167665681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 362880, while the sum is 46.

The square root of 167665681 is about 12948.5783389529. The cubic root of 167665681 is about 551.4185760382.

The spelling of 167665681 in words is "one hundred sixty-seven million, six hundred sixty-five thousand, six hundred eighty-one".