1326266561 has 2 divisors, whose sum is σ = 1326266562. Its totient is φ = 1326266560.

The previous prime is 1326266507. The next prime is 1326266569. The reversal of 1326266561 is 1656626231.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1297440400 + 28826161 = 36020^2 + 5369^2 .

It is a cyclic number.

It is not a de Polignac number, because 1326266561 - 2⁶ = 1326266497 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (1326266569) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 663133280 + 663133281.

It is an arithmetic number, because the mean of its divisors is an integer number (663133281).

Almost surely, 2^1326266561 is an apocalyptic number.

It is an amenable number.

1326266561 is a deficient number, since it is larger than the sum of its proper divisors (1).

1326266561 is an equidigital number, since it uses as much as digits as its factorization.

1326266561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 77760, while the sum is 38.

The square root of 1326266561 is about 36417.9428441531. The cubic root of 1326266561 is about 1098.6944734729.

The spelling of 1326266561 in words is "one billion, three hundred twenty-six million, two hundred sixty-six thousand, five hundred sixty-one".