51821865677 has 2 divisors, whose sum is σ = 51821865678. Its totient is φ = 51821865676.

The previous prime is 51821865673. The next prime is 51821865707. The reversal of 51821865677 is 77656812815.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 45343869481 + 6477996196 = 212941^2 + 80486^2 .

It is a cyclic number.

It is not a de Polignac number, because 51821865677 - 2² = 51821865673 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51821865671) 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, 25910932838 + 25910932839.

It is an arithmetic number, because the mean of its divisors is an integer number (25910932839).

Almost surely, 2^51821865677 is an apocalyptic number.

It is an amenable number.

51821865677 is a deficient number, since it is larger than the sum of its proper divisors (1).

51821865677 is an equidigital number, since it uses as much as digits as its factorization.

51821865677 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5644800, while the sum is 56.

The spelling of 51821865677 in words is "fifty-one billion, eight hundred twenty-one million, eight hundred sixty-five thousand, six hundred seventy-seven".