65800020661 has 2 divisors, whose sum is σ = 65800020662. Its totient is φ = 65800020660.

The previous prime is 65800020647. The next prime is 65800020679. The reversal of 65800020661 is 16602000856.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 59881026436 + 5918994225 = 244706^2 + 76935^2 .

It is a cyclic number.

It is not a de Polignac number, because 65800020661 - 2²⁷ = 65665802933 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (65800020691) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32900010330 + 32900010331.

It is an arithmetic number, because the mean of its divisors is an integer number (32900010331).

Almost surely, 2^65800020661 is an apocalyptic number.

It is an amenable number.

65800020661 is a deficient number, since it is larger than the sum of its proper divisors (1).

65800020661 is an equidigital number, since it uses as much as digits as its factorization.

65800020661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 17280, while the sum is 34.

The spelling of 65800020661 in words is "sixty-five billion, eight hundred million, twenty thousand, six hundred sixty-one".