66117509 has 2 divisors, whose sum is σ = 66117510. Its totient is φ = 66117508.

The previous prime is 66117481. The next prime is 66117517. The reversal of 66117509 is 90571166.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 39564100 + 26553409 = 6290^2 + 5153^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66117509 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66117559) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33058754 + 33058755.

It is an arithmetic number, because the mean of its divisors is an integer number (33058755).

Almost surely, 2^66117509 is an apocalyptic number.

It is an amenable number.

66117509 is a deficient number, since it is larger than the sum of its proper divisors (1).

66117509 is an equidigital number, since it uses as much as digits as its factorization.

66117509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11340, while the sum is 35.

The square root of 66117509 is about 8131.2673673911. The cubic root of 66117509 is about 404.3636992941.

The spelling of 66117509 in words is "sixty-six million, one hundred seventeen thousand, five hundred nine".