51905404861 has 2 divisors, whose sum is σ = 51905404862. Its totient is φ = 51905404860.

The previous prime is 51905404843. The next prime is 51905404879. The reversal of 51905404861 is 16840450915.

It is a balanced prime because it is at equal distance from previous prime (51905404843) and next prime (51905404879).

It can be written as a sum of positive squares in only one way, i.e., 26315003961 + 25590400900 = 162219^2 + 159970^2 .

It is a cyclic number.

It is not a de Polignac number, because 51905404861 - 2⁹ = 51905404349 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51905404561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25952702430 + 25952702431.

It is an arithmetic number, because the mean of its divisors is an integer number (25952702431).

Almost surely, 2^51905404861 is an apocalyptic number.

It is an amenable number.

51905404861 is a deficient number, since it is larger than the sum of its proper divisors (1).

51905404861 is an equidigital number, since it uses as much as digits as its factorization.

51905404861 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 172800, while the sum is 43.

The spelling of 51905404861 in words is "fifty-one billion, nine hundred five million, four hundred four thousand, eight hundred sixty-one".