73666561 has 2 divisors, whose sum is σ = 73666562. Its totient is φ = 73666560.

The previous prime is 73666529. The next prime is 73666597. The reversal of 73666561 is 16566637.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 64400625 + 9265936 = 8025^2 + 3044^2 .

It is an emirp because it is prime and its reverse (16566637) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 73666561 - 2⁵ = 73666529 is a prime.

It is not a weakly prime, because it can be changed into another prime (73666501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36833280 + 36833281.

It is an arithmetic number, because the mean of its divisors is an integer number (36833281).

Almost surely, 2^73666561 is an apocalyptic number.

It is an amenable number.

73666561 is a deficient number, since it is larger than the sum of its proper divisors (1).

73666561 is an equidigital number, since it uses as much as digits as its factorization.

73666561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 136080, while the sum is 40.

The square root of 73666561 is about 8582.9226374237. The cubic root of 73666561 is about 419.2021152052.

The spelling of 73666561 in words is "seventy-three million, six hundred sixty-six thousand, five hundred sixty-one".