66637718489 has 2 divisors, whose sum is σ = 66637718490. Its totient is φ = 66637718488.

The previous prime is 66637718453. The next prime is 66637718509. The reversal of 66637718489 is 98481773666.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 57293209600 + 9344508889 = 239360^2 + 96667^2 .

It is a cyclic number.

It is not a de Polignac number, because 66637718489 - 2⁸ = 66637718233 is a prime.

It is not a weakly prime, because it can be changed into another prime (66637718089) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33318859244 + 33318859245.

It is an arithmetic number, because the mean of its divisors is an integer number (33318859245).

Almost surely, 2^66637718489 is an apocalyptic number.

It is an amenable number.

66637718489 is a deficient number, since it is larger than the sum of its proper divisors (1).

66637718489 is an equidigital number, since it uses as much as digits as its factorization.

66637718489 is an evil number, because the sum of its binary digits is even.

The product of its digits is 73156608, while the sum is 65.

The spelling of 66637718489 in words is "sixty-six billion, six hundred thirty-seven million, seven hundred eighteen thousand, four hundred eighty-nine".