809011661 has 2 divisors, whose sum is σ = 809011662. Its totient is φ = 809011660.

The previous prime is 809011601. The next prime is 809011711. The reversal of 809011661 is 166110908.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 703045225 + 105966436 = 26515^2 + 10294^2 .

It is a cyclic number.

It is not a de Polignac number, because 809011661 - 2¹⁴ = 808995277 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (809011601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 404505830 + 404505831.

It is an arithmetic number, because the mean of its divisors is an integer number (404505831).

Almost surely, 2^809011661 is an apocalyptic number.

It is an amenable number.

809011661 is a deficient number, since it is larger than the sum of its proper divisors (1).

809011661 is an equidigital number, since it uses as much as digits as its factorization.

809011661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2592, while the sum is 32.

The square root of 809011661 is about 28443.1302953806. The cubic root of 809011661 is about 931.7904617906.

The spelling of 809011661 in words is "eight hundred nine million, eleven thousand, six hundred sixty-one".