1561605061 has 2 divisors, whose sum is σ = 1561605062. Its totient is φ = 1561605060.

The previous prime is 1561605043. The next prime is 1561605109. The reversal of 1561605061 is 1605061651.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1451229025 + 110376036 = 38095^2 + 10506^2 .

It is a cyclic number.

It is not a de Polignac number, because 1561605061 - 2¹⁷ = 1561473989 is a prime.

It is a super-2 number, since 2×1561605061² = 4877220733081627442, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1561605361) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 780802530 + 780802531.

It is an arithmetic number, because the mean of its divisors is an integer number (780802531).

Almost surely, 2^1561605061 is an apocalyptic number.

It is an amenable number.

1561605061 is a deficient number, since it is larger than the sum of its proper divisors (1).

1561605061 is an equidigital number, since it uses as much as digits as its factorization.

1561605061 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 31.

The square root of 1561605061 is about 39517.1489482731. The cubic root of 1561605061 is about 1160.1756226862.

The spelling of 1561605061 in words is "one billion, five hundred sixty-one million, six hundred five thousand, sixty-one".