66089561 has 2 divisors, whose sum is σ = 66089562. Its totient is φ = 66089560.

The previous prime is 66089503. The next prime is 66089563. The reversal of 66089561 is 16598066.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 43811161 + 22278400 = 6619^2 + 4720^2 .

It is a cyclic number.

It is not a de Polignac number, because 66089561 - 2¹⁴ = 66073177 is a prime.

It is a Sophie Germain prime.

Together with 66089563, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (66089563) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33044780 + 33044781.

It is an arithmetic number, because the mean of its divisors is an integer number (33044781).

Almost surely, 2^66089561 is an apocalyptic number.

It is an amenable number.

66089561 is a deficient number, since it is larger than the sum of its proper divisors (1).

66089561 is an equidigital number, since it uses as much as digits as its factorization.

66089561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 77760, while the sum is 41.

The square root of 66089561 is about 8129.5486344569. The cubic root of 66089561 is about 404.3067161563.

The spelling of 66089561 in words is "sixty-six million, eighty-nine thousand, five hundred sixty-one".