51661916797 has 2 divisors, whose sum is σ = 51661916798. Its totient is φ = 51661916796.

The previous prime is 51661916773. The next prime is 51661916819. The reversal of 51661916797 is 79761916615.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 31226070681 + 20435846116 = 176709^2 + 142954^2 .

It is a cyclic number.

It is not a de Polignac number, because 51661916797 - 2¹⁹ = 51661392509 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51661916737) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25830958398 + 25830958399.

It is an arithmetic number, because the mean of its divisors is an integer number (25830958399).

Almost surely, 2^51661916797 is an apocalyptic number.

It is an amenable number.

51661916797 is a deficient number, since it is larger than the sum of its proper divisors (1).

51661916797 is an equidigital number, since it uses as much as digits as its factorization.

51661916797 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4286520, while the sum is 58.

The spelling of 51661916797 in words is "fifty-one billion, six hundred sixty-one million, nine hundred sixteen thousand, seven hundred ninety-seven".