51686402987 has 2 divisors, whose sum is σ = 51686402988. Its totient is φ = 51686402986.

The previous prime is 51686402969. The next prime is 51686403037. The reversal of 51686402987 is 78920468615.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 51686402987 - 2¹⁸ = 51686140843 is a prime.

It is not a weakly prime, because it can be changed into another prime (51686402917) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25843201493 + 25843201494.

It is an arithmetic number, because the mean of its divisors is an integer number (25843201494).

Almost surely, 2^51686402987 is an apocalyptic number.

51686402987 is a deficient number, since it is larger than the sum of its proper divisors (1).

51686402987 is an equidigital number, since it uses as much as digits as its factorization.

51686402987 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5806080, while the sum is 56.

The spelling of 51686402987 in words is "fifty-one billion, six hundred eighty-six million, four hundred two thousand, nine hundred eighty-seven".