668779511 has 2 divisors, whose sum is σ = 668779512. Its totient is φ = 668779510.

The previous prime is 668779483. The next prime is 668779549. The reversal of 668779511 is 115977866.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-668779511 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 668779511.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (668779571) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334389755 + 334389756.

It is an arithmetic number, because the mean of its divisors is an integer number (334389756).

Almost surely, 2^668779511 is an apocalyptic number.

668779511 is a deficient number, since it is larger than the sum of its proper divisors (1).

668779511 is an equidigital number, since it uses as much as digits as its factorization.

668779511 is an evil number, because the sum of its binary digits is even.

The product of its digits is 635040, while the sum is 50.

The square root of 668779511 is about 25860.7716628874. The cubic root of 668779511 is about 874.5023612765.

The spelling of 668779511 in words is "six hundred sixty-eight million, seven hundred seventy-nine thousand, five hundred eleven".