51647578561 has 2 divisors, whose sum is σ = 51647578562. Its totient is φ = 51647578560.

The previous prime is 51647578529. The next prime is 51647578627. The reversal of 51647578561 is 16587574615.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 49709377936 + 1938200625 = 222956^2 + 44025^2 .

It is a cyclic number.

It is not a de Polignac number, because 51647578561 - 2⁵ = 51647578529 is a prime.

It is not a weakly prime, because it can be changed into another prime (51647579561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25823789280 + 25823789281.

It is an arithmetic number, because the mean of its divisors is an integer number (25823789281).

Almost surely, 2^51647578561 is an apocalyptic number.

It is an amenable number.

51647578561 is a deficient number, since it is larger than the sum of its proper divisors (1).

51647578561 is an equidigital number, since it uses as much as digits as its factorization.

51647578561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7056000, while the sum is 55.

The spelling of 51647578561 in words is "fifty-one billion, six hundred forty-seven million, five hundred seventy-eight thousand, five hundred sixty-one".