561981385729 has 2 divisors, whose sum is σ = 561981385730. Its totient is φ = 561981385728.

The previous prime is 561981385697. The next prime is 561981385789. The reversal of 561981385729 is 927583189165.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 559474080400 + 2507305329 = 747980^2 + 50073^2 .

It is a cyclic number.

It is not a de Polignac number, because 561981385729 - 2⁵ = 561981385697 is a prime.

It is a super-2 number, since 2×561981385729² (a number of 24 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (561981385789) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 280990692864 + 280990692865.

It is an arithmetic number, because the mean of its divisors is an integer number (280990692865).

Almost surely, 2^561981385729 is an apocalyptic number.

It is an amenable number.

561981385729 is a deficient number, since it is larger than the sum of its proper divisors (1).

561981385729 is an equidigital number, since it uses as much as digits as its factorization.

561981385729 is an evil number, because the sum of its binary digits is even.

The product of its digits is 32659200, while the sum is 64.

The spelling of 561981385729 in words is "five hundred sixty-one billion, nine hundred eighty-one million, three hundred eighty-five thousand, seven hundred twenty-nine".