10666957781 has 2 divisors, whose sum is σ = 10666957782. Its totient is φ = 10666957780.

The previous prime is 10666957771. The next prime is 10666957783. The reversal of 10666957781 is 18775966601.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10574008900 + 92948881 = 102830^2 + 9641^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-10666957781 is a prime.

It is a super-2 number, since 2×10666957781² (a number of 21 digits) contains 22 as substring.

Together with 10666957783, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (10666957783) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5333478890 + 5333478891.

It is an arithmetic number, because the mean of its divisors is an integer number (5333478891).

Almost surely, 2^10666957781 is an apocalyptic number.

It is an amenable number.

10666957781 is a deficient number, since it is larger than the sum of its proper divisors (1).

10666957781 is an equidigital number, since it uses as much as digits as its factorization.

10666957781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3810240, while the sum is 56.

The spelling of 10666957781 in words is "ten billion, six hundred sixty-six million, nine hundred fifty-seven thousand, seven hundred eighty-one".