2668778657 has 2 divisors, whose sum is σ = 2668778658. Its totient is φ = 2668778656.

The previous prime is 2668778641. The next prime is 2668778687. The reversal of 2668778657 is 7568778662.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2508907921 + 159870736 = 50089^2 + 12644^2 .

It is a cyclic number.

It is not a de Polignac number, because 2668778657 - 2⁴ = 2668778641 is a prime.

It is a super-3 number, since 3×2668778657³ (a number of 29 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 2668778657.

It is not a weakly prime, because it can be changed into another prime (2668778687) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1334389328 + 1334389329.

It is an arithmetic number, because the mean of its divisors is an integer number (1334389329).

Almost surely, 2^2668778657 is an apocalyptic number.

It is an amenable number.

2668778657 is a deficient number, since it is larger than the sum of its proper divisors (1).

2668778657 is an equidigital number, since it uses as much as digits as its factorization.

2668778657 is an evil number, because the sum of its binary digits is even.

The product of its digits is 47416320, while the sum is 62.

The square root of 2668778657 is about 51660.2231605710. The cubic root of 2668778657 is about 1387.0885451729.

The spelling of 2668778657 in words is "two billion, six hundred sixty-eight million, seven hundred seventy-eight thousand, six hundred fifty-seven".