1561061270581 has 2 divisors, whose sum is σ = 1561061270582. Its totient is φ = 1561061270580.

The previous prime is 1561061270533. The next prime is 1561061270599. The reversal of 1561061270581 is 1850721601651.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1440264012100 + 120797258481 = 1200110^2 + 347559^2 .

It is a cyclic number.

It is not a de Polignac number, because 1561061270581 - 2¹³ = 1561061262389 is a prime.

It is a super-2 number, since 2×1561061270581² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1561061270501) 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, 780530635290 + 780530635291.

It is an arithmetic number, because the mean of its divisors is an integer number (780530635291).

Almost surely, 2^{1561061270581} is an apocalyptic number.

It is an amenable number.

1561061270581 is a deficient number, since it is larger than the sum of its proper divisors (1).

1561061270581 is an equidigital number, since it uses as much as digits as its factorization.

1561061270581 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 100800, while the sum is 43.

The spelling of 1561061270581 in words is "one trillion, five hundred sixty-one billion, sixty-one million, two hundred seventy thousand, five hundred eighty-one".