51145561 has 2 divisors, whose sum is σ = 51145562. Its totient is φ = 51145560.

The previous prime is 51145553. The next prime is 51145603. The reversal of 51145561 is 16554115.

It is a happy number.

51145561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 50055625 + 1089936 = 7075^2 + 1044^2 .

It is a cyclic number.

It is not a de Polignac number, because 51145561 - 2³ = 51145553 is a prime.

It is not a weakly prime, because it can be changed into another prime (51149561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25572780 + 25572781.

It is an arithmetic number, because the mean of its divisors is an integer number (25572781).

Almost surely, 2^51145561 is an apocalyptic number.

It is an amenable number.

51145561 is a deficient number, since it is larger than the sum of its proper divisors (1).

51145561 is an equidigital number, since it uses as much as digits as its factorization.

51145561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3000, while the sum is 28.

The square root of 51145561 is about 7151.6124755191. The cubic root of 51145561 is about 371.1954540517.

Adding to 51145561 its reverse (16554115), we get a palindrome (67699676).

The spelling of 51145561 in words is "fifty-one million, one hundred forty-five thousand, five hundred sixty-one".