66690389 has 2 divisors, whose sum is σ = 66690390. Its totient is φ = 66690388.

The previous prime is 66690347. The next prime is 66690413. The reversal of 66690389 is 98309666.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 45832900 + 20857489 = 6770^2 + 4567^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66690389 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66690319) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33345194 + 33345195.

It is an arithmetic number, because the mean of its divisors is an integer number (33345195).

Almost surely, 2^66690389 is an apocalyptic number.

It is an amenable number.

66690389 is a deficient number, since it is larger than the sum of its proper divisors (1).

66690389 is an equidigital number, since it uses as much as digits as its factorization.

66690389 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 419904, while the sum is 47.

The square root of 66690389 is about 8166.4183703751. The cubic root of 66690389 is about 405.5282220091.

The spelling of 66690389 in words is "sixty-six million, six hundred ninety thousand, three hundred eighty-nine".