65131981657 has 2 divisors, whose sum is σ = 65131981658. Its totient is φ = 65131981656.

The previous prime is 65131981637. The next prime is 65131981699. The reversal of 65131981657 is 75618913156.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 55648338201 + 9483643456 = 235899^2 + 97384^2 .

It is a cyclic number.

It is not a de Polignac number, because 65131981657 - 2⁷ = 65131981529 is a prime.

It is not a weakly prime, because it can be changed into another prime (65131981637) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32565990828 + 32565990829.

It is an arithmetic number, because the mean of its divisors is an integer number (32565990829).

Almost surely, 2^65131981657 is an apocalyptic number.

It is an amenable number.

65131981657 is a deficient number, since it is larger than the sum of its proper divisors (1).

65131981657 is an equidigital number, since it uses as much as digits as its factorization.

65131981657 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1360800, while the sum is 52.

The spelling of 65131981657 in words is "sixty-five billion, one hundred thirty-one million, nine hundred eighty-one thousand, six hundred fifty-seven".