65656665661 has 2 divisors, whose sum is σ = 65656665662. Its totient is φ = 65656665660.

The previous prime is 65656665589. The next prime is 65656665691. The reversal of 65656665661 is 16656665656.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 49226296900 + 16430368761 = 221870^2 + 128181^2 .

It is a cyclic number.

It is not a de Polignac number, because 65656665661 - 2¹⁵ = 65656632893 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 65656665596 and 65656665605.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (65656665691) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32828332830 + 32828332831.

It is an arithmetic number, because the mean of its divisors is an integer number (32828332831).

Almost surely, 2^65656665661 is an apocalyptic number.

It is an amenable number.

65656665661 is a deficient number, since it is larger than the sum of its proper divisors (1).

65656665661 is an equidigital number, since it uses as much as digits as its factorization.

65656665661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 34992000, while the sum is 58.

It can be divided in two parts, 656566 and 65661, that added together give a palindrome (722227).

The spelling of 65656665661 in words is "sixty-five billion, six hundred fifty-six million, six hundred sixty-five thousand, six hundred sixty-one".