1288009661 has 2 divisors, whose sum is σ = 1288009662. Its totient is φ = 1288009660.

The previous prime is 1288009649. The next prime is 1288009663. The reversal of 1288009661 is 1669008821.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1222900900 + 65108761 = 34970^2 + 8069^2 .

It is a cyclic number.

It is not a de Polignac number, because 1288009661 - 2¹⁴ = 1287993277 is a prime.

It is a Sophie Germain prime.

Together with 1288009663, 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 (1288009663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 644004830 + 644004831.

It is an arithmetic number, because the mean of its divisors is an integer number (644004831).

Almost surely, 2^1288009661 is an apocalyptic number.

It is an amenable number.

1288009661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1288009661 is an equidigital number, since it uses as much as digits as its factorization.

1288009661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 41472, while the sum is 41.

The square root of 1288009661 is about 35888.8514862206. The cubic root of 1288009661 is about 1088.0270854187.

The spelling of 1288009661 in words is "one billion, two hundred eighty-eight million, nine thousand, six hundred sixty-one".