665181667 has 2 divisors, whose sum is σ = 665181668. Its totient is φ = 665181666.

The previous prime is 665181623. The next prime is 665181683. The reversal of 665181667 is 766181566.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 665181667 - 2¹⁵ = 665148899 is a prime.

It is a super-2 number, since 2×665181667² = 884933300225797778, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (665181067) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332590833 + 332590834.

It is an arithmetic number, because the mean of its divisors is an integer number (332590834).

Almost surely, 2^665181667 is an apocalyptic number.

665181667 is a deficient number, since it is larger than the sum of its proper divisors (1).

665181667 is an equidigital number, since it uses as much as digits as its factorization.

665181667 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 665181667 is about 25791.1160479728. The cubic root of 665181667 is about 872.9313491798.

The spelling of 665181667 in words is "six hundred sixty-five million, one hundred eighty-one thousand, six hundred sixty-seven".