51978530861 has 2 divisors, whose sum is σ = 51978530862. Its totient is φ = 51978530860.

The previous prime is 51978530833. The next prime is 51978530867. The reversal of 51978530861 is 16803587915.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 46083208900 + 5895321961 = 214670^2 + 76781^2 .

It is a cyclic number.

It is not a de Polignac number, because 51978530861 - 2¹⁴ = 51978514477 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51978530867) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25989265430 + 25989265431.

It is an arithmetic number, because the mean of its divisors is an integer number (25989265431).

Almost surely, 2^51978530861 is an apocalyptic number.

It is an amenable number.

51978530861 is a deficient number, since it is larger than the sum of its proper divisors (1).

51978530861 is an equidigital number, since it uses as much as digits as its factorization.

51978530861 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1814400, while the sum is 53.

The spelling of 51978530861 in words is "fifty-one billion, nine hundred seventy-eight million, five hundred thirty thousand, eight hundred sixty-one".