51681043439 has 2 divisors, whose sum is σ = 51681043440. Its totient is φ = 51681043438.

The previous prime is 51681043397. The next prime is 51681043459. The reversal of 51681043439 is 93434018615.

51681043439 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51681043439 is a prime.

It is a Sophie Germain prime.

It is a self number, because there is not a number n which added to its sum of digits gives 51681043439.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51681043459) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25840521719 + 25840521720.

It is an arithmetic number, because the mean of its divisors is an integer number (25840521720).

Almost surely, 2^51681043439 is an apocalyptic number.

51681043439 is a deficient number, since it is larger than the sum of its proper divisors (1).

51681043439 is an equidigital number, since it uses as much as digits as its factorization.

51681043439 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 311040, while the sum is 44.

The spelling of 51681043439 in words is "fifty-one billion, six hundred eighty-one million, forty-three thousand, four hundred thirty-nine".