51355380821 has 2 divisors, whose sum is σ = 51355380822. Its totient is φ = 51355380820.

The previous prime is 51355380803. The next prime is 51355380827. The reversal of 51355380821 is 12808355315.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 50043927025 + 1311453796 = 223705^2 + 36214^2 .

It is a cyclic number.

It is not a de Polignac number, because 51355380821 - 2¹⁰ = 51355379797 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51355380827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25677690410 + 25677690411.

It is an arithmetic number, because the mean of its divisors is an integer number (25677690411).

Almost surely, 2^51355380821 is an apocalyptic number.

It is an amenable number.

51355380821 is a deficient number, since it is larger than the sum of its proper divisors (1).

51355380821 is an equidigital number, since it uses as much as digits as its factorization.

51355380821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 144000, while the sum is 41.

The spelling of 51355380821 in words is "fifty-one billion, three hundred fifty-five million, three hundred eighty thousand, eight hundred twenty-one".