66615589 has 2 divisors, whose sum is σ = 66615590. Its totient is φ = 66615588.

The previous prime is 66615583. The next prime is 66615607. The reversal of 66615589 is 98551666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 64160100 + 2455489 = 8010^2 + 1567^2 .

It is a cyclic number.

It is not a de Polignac number, because 66615589 - 2⁹ = 66615077 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66615583) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33307794 + 33307795.

It is an arithmetic number, because the mean of its divisors is an integer number (33307795).

Almost surely, 2^66615589 is an apocalyptic number.

It is an amenable number.

66615589 is a deficient number, since it is larger than the sum of its proper divisors (1).

66615589 is an equidigital number, since it uses as much as digits as its factorization.

66615589 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 388800, while the sum is 46.

The square root of 66615589 is about 8161.8373544197. The cubic root of 66615589 is about 405.3765516849.

The spelling of 66615589 in words is "sixty-six million, six hundred fifteen thousand, five hundred eighty-nine".