669686779 has 2 divisors, whose sum is σ = 669686780. Its totient is φ = 669686778.

The previous prime is 669686777. The next prime is 669686783. The reversal of 669686779 is 977686966.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 669686779 - 2¹ = 669686777 is a prime.

It is a super-3 number, since 3×669686779³ (a number of 27 digits) contains 333 as substring.

Together with 669686777, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 669686779.

It is not a weakly prime, because it can be changed into another prime (669686777) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334843389 + 334843390.

It is an arithmetic number, because the mean of its divisors is an integer number (334843390).

Almost surely, 2^669686779 is an apocalyptic number.

669686779 is a deficient number, since it is larger than the sum of its proper divisors (1).

669686779 is an equidigital number, since it uses as much as digits as its factorization.

669686779 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 41150592, while the sum is 64.

The square root of 669686779 is about 25878.3071123287. The cubic root of 669686779 is about 874.8976333034.

The spelling of 669686779 in words is "six hundred sixty-nine million, six hundred eighty-six thousand, seven hundred seventy-nine".