666777799 has 2 divisors, whose sum is σ = 666777800. Its totient is φ = 666777798.

The previous prime is 666777781. The next prime is 666777803. The reversal of 666777799 is 997777666.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 666777799 - 2¹⁵ = 666745031 is a prime.

It is a super-3 number, since 3×666777799³ (a number of 27 digits) contains 333 as substring.

It is a plaindrome in base 10.

It is a zygodrome in base 10.

It is a self number, because there is not a number n which added to its sum of digits gives 666777799.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (666777779) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333388899 + 333388900.

It is an arithmetic number, because the mean of its divisors is an integer number (333388900).

Almost surely, 2^666777799 is an apocalyptic number.

666777799 is a deficient number, since it is larger than the sum of its proper divisors (1).

666777799 is an equidigital number, since it uses as much as digits as its factorization.

666777799 is an evil number, because the sum of its binary digits is even.

The product of its digits is 42007896, while the sum is 64.

The square root of 666777799 is about 25822.0409534181. The cubic root of 666777799 is about 873.6290035570.

The spelling of 666777799 in words is "six hundred sixty-six million, seven hundred seventy-seven thousand, seven hundred ninety-nine".