51681463991 has 2 divisors, whose sum is σ = 51681463992. Its totient is φ = 51681463990.

The previous prime is 51681463961. The next prime is 51681464027. The reversal of 51681463991 is 19936418615.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51681463991 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51681463961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25840731995 + 25840731996.

It is an arithmetic number, because the mean of its divisors is an integer number (25840731996).

Almost surely, 2^51681463991 is an apocalyptic number.

51681463991 is a deficient number, since it is larger than the sum of its proper divisors (1).

51681463991 is an equidigital number, since it uses as much as digits as its factorization.

51681463991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1399680, while the sum is 53.

The spelling of 51681463991 in words is "fifty-one billion, six hundred eighty-one million, four hundred sixty-three thousand, nine hundred ninety-one".