61662940561 has 2 divisors, whose sum is σ = 61662940562. Its totient is φ = 61662940560.

The previous prime is 61662940541. The next prime is 61662940589. The reversal of 61662940561 is 16504926616.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 38855900161 + 22807040400 = 197119^2 + 151020^2 .

It is a cyclic number.

It is not a de Polignac number, because 61662940561 - 2²⁹ = 61126069649 is a prime.

It is not a weakly prime, because it can be changed into another prime (61662940541) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30831470280 + 30831470281.

It is an arithmetic number, because the mean of its divisors is an integer number (30831470281).

Almost surely, 2^61662940561 is an apocalyptic number.

It is an amenable number.

61662940561 is a deficient number, since it is larger than the sum of its proper divisors (1).

61662940561 is an equidigital number, since it uses as much as digits as its factorization.

61662940561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 466560, while the sum is 46.

The spelling of 61662940561 in words is "sixty-one billion, six hundred sixty-two million, nine hundred forty thousand, five hundred sixty-one".