2666691869 has 2 divisors, whose sum is σ = 2666691870. Its totient is φ = 2666691868.

The previous prime is 2666691823. The next prime is 2666691871. The reversal of 2666691869 is 9681966662.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2649160900 + 17530969 = 51470^2 + 4187^2 .

It is a cyclic number.

It is not a de Polignac number, because 2666691869 - 2⁸ = 2666691613 is a prime.

It is a super-2 number, since 2×2666691869² = 14222491048381426322, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 2666691871, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2666691169) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1333345934 + 1333345935.

It is an arithmetic number, because the mean of its divisors is an integer number (1333345935).

Almost surely, 2^2666691869 is an apocalyptic number.

It is an amenable number.

2666691869 is a deficient number, since it is larger than the sum of its proper divisors (1).

2666691869 is an equidigital number, since it uses as much as digits as its factorization.

2666691869 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10077696, while the sum is 59.

The square root of 2666691869 is about 51640.0219693989. The cubic root of 2666691869 is about 1386.7269172680.

The spelling of 2666691869 in words is "two billion, six hundred sixty-six million, six hundred ninety-one thousand, eight hundred sixty-nine".