668665069 has 2 divisors, whose sum is σ = 668665070. Its totient is φ = 668665068.

The previous prime is 668665051. The next prime is 668665111. The reversal of 668665069 is 960566866.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 391842025 + 276823044 = 19795^2 + 16638^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-668665069 is a prime.

It is a super-2 number, since 2×668665069² = 894225949001549522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (668665169) 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, 334332534 + 334332535.

It is an arithmetic number, because the mean of its divisors is an integer number (334332535).

Almost surely, 2^668665069 is an apocalyptic number.

It is an amenable number.

668665069 is a deficient number, since it is larger than the sum of its proper divisors (1).

668665069 is an equidigital number, since it uses as much as digits as its factorization.

668665069 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2799360, while the sum is 52.

The square root of 668665069 is about 25858.5589118961. The cubic root of 668665069 is about 874.4524766201.

The spelling of 668665069 in words is "six hundred sixty-eight million, six hundred sixty-five thousand, sixty-nine".