1223509561 has 2 divisors, whose sum is σ = 1223509562. Its totient is φ = 1223509560.

The previous prime is 1223509549. The next prime is 1223509591. The reversal of 1223509561 is 1659053221.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 664659961 + 558849600 = 25781^2 + 23640^2 .

It is a cyclic number.

It is not a de Polignac number, because 1223509561 - 2²³ = 1215120953 is a prime.

It is not a weakly prime, because it can be changed into another prime (1223509591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 611754780 + 611754781.

It is an arithmetic number, because the mean of its divisors is an integer number (611754781).

Almost surely, 2^1223509561 is an apocalyptic number.

It is an amenable number.

1223509561 is a deficient number, since it is larger than the sum of its proper divisors (1).

1223509561 is an equidigital number, since it uses as much as digits as its factorization.

1223509561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16200, while the sum is 34.

The square root of 1223509561 is about 34978.7015339335. The cubic root of 1223509561 is about 1069.5533585847.

The spelling of 1223509561 in words is "one billion, two hundred twenty-three million, five hundred nine thousand, five hundred sixty-one".