65646664657 has 16 divisors (see below), whose sum is σ = 75740313600. Its totient is φ = 55733789520.

The previous prime is 65646664649. The next prime is 65646664669. The reversal of 65646664657 is 75646664656.

It is a cyclic number.

It is not a de Polignac number, because 65646664657 - 2³ = 65646664649 is a prime.

It is a super-2 number, since 2×65646664657² (a number of 22 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 65646664595 and 65646664604.

It is not an unprimeable number, because it can be changed into a prime (65646664627) 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 in 15 ways as a sum of consecutive naturals, for example, 341094 + ... + 497632.

It is an arithmetic number, because the mean of its divisors is an integer number (4733769600).

Almost surely, 2^65646664657 is an apocalyptic number.

It is an amenable number.

65646664657 is a deficient number, since it is larger than the sum of its proper divisors (10093648943).

65646664657 is a wasteful number, since it uses less digits than its factorization.

65646664657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 157116.

The product of its digits is 130636800, while the sum is 61.

Subtracting 65646664657 from its reverse (75646664656), we obtain a palindrome (9999999999).

The spelling of 65646664657 in words is "sixty-five billion, six hundred forty-six million, six hundred sixty-four thousand, six hundred fifty-seven".