8661142561 has 2 divisors, whose sum is σ = 8661142562. Its totient is φ = 8661142560.

The previous prime is 8661142549. The next prime is 8661142573. The reversal of 8661142561 is 1652411668.

It is a balanced prime because it is at equal distance from previous prime (8661142549) and next prime (8661142573).

It can be written as a sum of positive squares in only one way, i.e., 8580502161 + 80640400 = 92631^2 + 8980^2 .

It is a cyclic number.

It is not a de Polignac number, because 8661142561 - 2¹¹ = 8661140513 is a prime.

It is not a weakly prime, because it can be changed into another prime (8661142531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4330571280 + 4330571281.

It is an arithmetic number, because the mean of its divisors is an integer number (4330571281).

Almost surely, 2^8661142561 is an apocalyptic number.

It is an amenable number.

8661142561 is a deficient number, since it is larger than the sum of its proper divisors (1).

8661142561 is an equidigital number, since it uses as much as digits as its factorization.

8661142561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 69120, while the sum is 40.

The square root of 8661142561 is about 93065.2596891020. The cubic root of 8661142561 is about 2053.6435351369.

The spelling of 8661142561 in words is "eight billion, six hundred sixty-one million, one hundred forty-two thousand, five hundred sixty-one".