1001561549 has 2 divisors, whose sum is σ = 1001561550. Its totient is φ = 1001561548.

The previous prime is 1001561479. The next prime is 1001561557. The reversal of 1001561549 is 9451651001.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 938993449 + 62568100 = 30643^2 + 7910^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1001561549 is a prime.

It is a Sophie Germain 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 (1001561849) 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, 500780774 + 500780775.

It is an arithmetic number, because the mean of its divisors is an integer number (500780775).

Almost surely, 2^1001561549 is an apocalyptic number.

It is an amenable number.

1001561549 is a deficient number, since it is larger than the sum of its proper divisors (1).

1001561549 is an equidigital number, since it uses as much as digits as its factorization.

1001561549 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5400, while the sum is 32.

The square root of 1001561549 is about 31647.4572280302. The cubic root of 1001561549 is about 1000.5202456309.

The spelling of 1001561549 in words is "one billion, one million, five hundred sixty-one thousand, five hundred forty-nine".