61505005561 has 2 divisors, whose sum is σ = 61505005562. Its totient is φ = 61505005560.

The previous prime is 61505005531. The next prime is 61505005591. The reversal of 61505005561 is 16550050516.

It is a balanced prime because it is at equal distance from previous prime (61505005531) and next prime (61505005591).

It can be written as a sum of positive squares in only one way, i.e., 60991711225 + 513294336 = 246965^2 + 22656^2 .

It is a cyclic number.

It is not a de Polignac number, because 61505005561 - 2¹³ = 61504997369 is a prime.

It is not a weakly prime, because it can be changed into another prime (61505005531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30752502780 + 30752502781.

It is an arithmetic number, because the mean of its divisors is an integer number (30752502781).

Almost surely, 2^61505005561 is an apocalyptic number.

It is an amenable number.

61505005561 is a deficient number, since it is larger than the sum of its proper divisors (1).

61505005561 is an equidigital number, since it uses as much as digits as its factorization.

61505005561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 22500, while the sum is 34.

The spelling of 61505005561 in words is "sixty-one billion, five hundred five million, five thousand, five hundred sixty-one".