2666666657 has 2 divisors, whose sum is σ = 2666666658. Its totient is φ = 2666666656.

The previous prime is 2666666623. The next prime is 2666666659. The reversal of 2666666657 is 7566666662.

2666666657 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2271094336 + 395572321 = 47656^2 + 19889^2 .

It is a cyclic number.

It is not a de Polignac number, because 2666666657 - 2¹⁰ = 2666665633 is a prime.

It is a super-2 number, since 2×2666666657² = 14222222119111111298, which contains 22 as substring.

Together with 2666666659, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (2666666659) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1333333328 + 1333333329.

It is an arithmetic number, because the mean of its divisors is an integer number (1333333329).

Almost surely, 2^2666666657 is an apocalyptic number.

It is an amenable number.

2666666657 is a deficient number, since it is larger than the sum of its proper divisors (1).

2666666657 is an equidigital number, since it uses as much as digits as its factorization.

2666666657 is an evil number, because the sum of its binary digits is even.

The product of its digits is 19595520, while the sum is 56.

The square root of 2666666657 is about 51639.7778558351. Note that the first 3 decimals coincide. The cubic root of 2666666657 is about 1386.7225470256.

The spelling of 2666666657 in words is "two billion, six hundred sixty-six million, six hundred sixty-six thousand, six hundred fifty-seven".