65561215549 has 2 divisors, whose sum is σ = 65561215550. Its totient is φ = 65561215548.

The previous prime is 65561215541. The next prime is 65561215571. The reversal of 65561215549 is 94551216556.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 46487672100 + 19073543449 = 215610^2 + 138107^2 .

It is a cyclic number.

It is not a de Polignac number, because 65561215549 - 2³ = 65561215541 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (65561215541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32780607774 + 32780607775.

It is an arithmetic number, because the mean of its divisors is an integer number (32780607775).

Almost surely, 2^65561215549 is an apocalyptic number.

It is an amenable number.

65561215549 is a deficient number, since it is larger than the sum of its proper divisors (1).

65561215549 is an equidigital number, since it uses as much as digits as its factorization.

65561215549 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1620000, while the sum is 49.

The spelling of 65561215549 in words is "sixty-five billion, five hundred sixty-one million, two hundred fifteen thousand, five hundred forty-nine".