723845561 has 2 divisors, whose sum is σ = 723845562. Its totient is φ = 723845560.

The previous prime is 723845519. The next prime is 723845579. The reversal of 723845561 is 165548327.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 521665600 + 202179961 = 22840^2 + 14219^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-723845561 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 (723845461) 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, 361922780 + 361922781.

It is an arithmetic number, because the mean of its divisors is an integer number (361922781).

Almost surely, 2^723845561 is an apocalyptic number.

It is an amenable number.

723845561 is a deficient number, since it is larger than the sum of its proper divisors (1).

723845561 is an equidigital number, since it uses as much as digits as its factorization.

723845561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 201600, while the sum is 41.

The square root of 723845561 is about 26904.3781009709. The cubic root of 723845561 is about 897.8738126732.

The spelling of 723845561 in words is "seven hundred twenty-three million, eight hundred forty-five thousand, five hundred sixty-one".