1005755561 has 2 divisors, whose sum is σ = 1005755562. Its totient is φ = 1005755560.

The previous prime is 1005755521. The next prime is 1005755563. The reversal of 1005755561 is 1655575001.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 983136025 + 22619536 = 31355^2 + 4756^2 .

It is a cyclic number.

It is not a de Polignac number, because 1005755561 - 2¹⁰ = 1005754537 is a prime.

Together with 1005755563, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1005755563) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 502877780 + 502877781.

It is an arithmetic number, because the mean of its divisors is an integer number (502877781).

Almost surely, 2^1005755561 is an apocalyptic number.

It is an amenable number.

1005755561 is a deficient number, since it is larger than the sum of its proper divisors (1).

1005755561 is an equidigital number, since it uses as much as digits as its factorization.

1005755561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 26250, while the sum is 35.

The square root of 1005755561 is about 31713.6494431026. The cubic root of 1005755561 is about 1001.9148513373.

The spelling of 1005755561 in words is "one billion, five million, seven hundred fifty-five thousand, five hundred sixty-one".