1561280741 has 2 divisors, whose sum is σ = 1561280742. Its totient is φ = 1561280740.

The previous prime is 1561280717. The next prime is 1561280761. The reversal of 1561280741 is 1470821651.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1538992900 + 22287841 = 39230^2 + 4721^2 .

It is a cyclic number.

It is not a de Polignac number, because 1561280741 - 2²² = 1557086437 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 (1561280761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 780640370 + 780640371.

It is an arithmetic number, because the mean of its divisors is an integer number (780640371).

Almost surely, 2^1561280741 is an apocalyptic number.

It is an amenable number.

1561280741 is a deficient number, since it is larger than the sum of its proper divisors (1).

1561280741 is an equidigital number, since it uses as much as digits as its factorization.

1561280741 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13440, while the sum is 35.

The square root of 1561280741 is about 39513.0452002880. The cubic root of 1561280741 is about 1160.0953005829.

The spelling of 1561280741 in words is "one billion, five hundred sixty-one million, two hundred eighty thousand, seven hundred forty-one".