916666661 has 2 divisors, whose sum is σ = 916666662. Its totient is φ = 916666660.

The previous prime is 916666649. The next prime is 916666687. The reversal of 916666661 is 166666619.

916666661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 912402436 + 4264225 = 30206^2 + 2065^2 .

It is a cyclic number.

It is not a de Polignac number, because 916666661 - 2¹⁰ = 916665637 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a fibodiv number, since the Fibonacci-like sequence with seeds 9 and 16666661 contains 916666661 itself.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (916665661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 458333330 + 458333331.

It is an arithmetic number, because the mean of its divisors is an integer number (458333331).

Almost surely, 2^916666661 is an apocalyptic number.

It is an amenable number.

916666661 is a deficient number, since it is larger than the sum of its proper divisors (1).

916666661 is an equidigital number, since it uses as much as digits as its factorization.

916666661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 419904, while the sum is 47.

The square root of 916666661 is about 30276.5034473930. The cubic root of 916666661 is about 971.4127785402.

The spelling of 916666661 in words is "nine hundred sixteen million, six hundred sixty-six thousand, six hundred sixty-one".