1561307117 has 2 divisors, whose sum is σ = 1561307118. Its totient is φ = 1561307116.

The previous prime is 1561307113. The next prime is 1561307131. The reversal of 1561307117 is 7117031651.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1540641001 + 20666116 = 39251^2 + 4546^2 .

It is a cyclic number.

It is not a de Polignac number, because 1561307117 - 2² = 1561307113 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1561307113) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 780653558 + 780653559.

It is an arithmetic number, because the mean of its divisors is an integer number (780653559).

Almost surely, 2^1561307117 is an apocalyptic number.

It is an amenable number.

1561307117 is a deficient number, since it is larger than the sum of its proper divisors (1).

1561307117 is an equidigital number, since it uses as much as digits as its factorization.

1561307117 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4410, while the sum is 32.

The square root of 1561307117 is about 39513.3789620680. The cubic root of 1561307117 is about 1160.1018333609.

Adding to 1561307117 its reverse (7117031651), we get a palindrome (8678338768).

The spelling of 1561307117 in words is "one billion, five hundred sixty-one million, three hundred seven thousand, one hundred seventeen".