66499817497 has 2 divisors, whose sum is σ = 66499817498. Its totient is φ = 66499817496.

The previous prime is 66499817479. The next prime is 66499817533. The reversal of 66499817497 is 79471899466.

Together with previous prime (66499817479) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 66224390281 + 275427216 = 257341^2 + 16596^2 .

It is a cyclic number.

It is not a de Polignac number, because 66499817497 - 2³¹ = 64352333849 is a prime.

It is not a weakly prime, because it can be changed into another prime (66499317497) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33249908748 + 33249908749.

It is an arithmetic number, because the mean of its divisors is an integer number (33249908749).

Almost surely, 2^66499817497 is an apocalyptic number.

It is an amenable number.

66499817497 is a deficient number, since it is larger than the sum of its proper divisors (1).

66499817497 is an equidigital number, since it uses as much as digits as its factorization.

66499817497 is an evil number, because the sum of its binary digits is even.

The product of its digits is 164602368, while the sum is 70.

The spelling of 66499817497 in words is "sixty-six billion, four hundred ninety-nine million, eight hundred seventeen thousand, four hundred ninety-seven".