66698669 has 2 divisors, whose sum is σ = 66698670. Its totient is φ = 66698668.

The previous prime is 66698659. The next prime is 66698699. The reversal of 66698669 is 96689666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 64561225 + 2137444 = 8035^2 + 1462^2 .

It is a cyclic number.

It is not a de Polignac number, because 66698669 - 2²⁴ = 49921453 is a prime.

It is a super-2 number, since 2×66698669² = 8897424892743122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66698659) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33349334 + 33349335.

It is an arithmetic number, because the mean of its divisors is an integer number (33349335).

Almost surely, 2^66698669 is an apocalyptic number.

It is an amenable number.

66698669 is a deficient number, since it is larger than the sum of its proper divisors (1).

66698669 is an equidigital number, since it uses as much as digits as its factorization.

66698669 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5038848, while the sum is 56.

The square root of 66698669 is about 8166.9253088295. The cubic root of 66698669 is about 405.5450042111.

The spelling of 66698669 in words is "sixty-six million, six hundred ninety-eight thousand, six hundred sixty-nine".