51249845861 has 2 divisors, whose sum is σ = 51249845862. Its totient is φ = 51249845860.

The previous prime is 51249845851. The next prime is 51249845863. The reversal of 51249845861 is 16854894215.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 51141561025 + 108284836 = 226145^2 + 10406^2 .

It is a cyclic number.

It is not a de Polignac number, because 51249845861 - 2¹⁸ = 51249583717 is a prime.

Together with 51249845863, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51249845863) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25624922930 + 25624922931.

It is an arithmetic number, because the mean of its divisors is an integer number (25624922931).

Almost surely, 2^51249845861 is an apocalyptic number.

It is an amenable number.

51249845861 is a deficient number, since it is larger than the sum of its proper divisors (1).

51249845861 is an equidigital number, since it uses as much as digits as its factorization.

51249845861 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2764800, while the sum is 53.

The spelling of 51249845861 in words is "fifty-one billion, two hundred forty-nine million, eight hundred forty-five thousand, eight hundred sixty-one".