51020685817 has 2 divisors, whose sum is σ = 51020685818. Its totient is φ = 51020685816.

The previous prime is 51020685809. The next prime is 51020685827. The reversal of 51020685817 is 71858602015.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 40120490601 + 10900195216 = 200301^2 + 104404^2 .

It is a cyclic number.

It is not a de Polignac number, because 51020685817 - 2³ = 51020685809 is a prime.

It is a super-2 number, since 2×51020685817² (a number of 22 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (51020685827) 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, 25510342908 + 25510342909.

It is an arithmetic number, because the mean of its divisors is an integer number (25510342909).

Almost surely, 2^51020685817 is an apocalyptic number.

It is an amenable number.

51020685817 is a deficient number, since it is larger than the sum of its proper divisors (1).

51020685817 is an equidigital number, since it uses as much as digits as its factorization.

51020685817 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 134400, while the sum is 43.

The spelling of 51020685817 in words is "fifty-one billion, twenty million, six hundred eighty-five thousand, eight hundred seventeen".