66408569 has 2 divisors, whose sum is σ = 66408570. Its totient is φ = 66408568.

The previous prime is 66408557. The next prime is 66408583. The reversal of 66408569 is 96580466.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 54760000 + 11648569 = 7400^2 + 3413^2 .

It is a cyclic number.

It is not a de Polignac number, because 66408569 - 2⁸ = 66408313 is a prime.

It is a super-2 number, since 2×66408569² = 8820196073255522, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (66402569) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33204284 + 33204285.

It is an arithmetic number, because the mean of its divisors is an integer number (33204285).

Almost surely, 2^66408569 is an apocalyptic number.

It is an amenable number.

66408569 is a deficient number, since it is larger than the sum of its proper divisors (1).

66408569 is an equidigital number, since it uses as much as digits as its factorization.

66408569 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 311040, while the sum is 44.

The square root of 66408569 is about 8149.1452926058. The cubic root of 66408569 is about 404.9561889306.

The spelling of 66408569 in words is "sixty-six million, four hundred eight thousand, five hundred sixty-nine".