66940389 has 6 divisors (see below), whose sum is σ = 96691686. Its totient is φ = 44626920.

The previous prime is 66940387. The next prime is 66940411. The reversal of 66940389 is 98304966.

It can be written as a sum of positive squares in only one way, i.e., 52056225 + 14884164 = 7215^2 + 3858^2 .

It is not a de Polignac number, because 66940389 - 2¹ = 66940387 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66940387) 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 in 5 ways as a sum of consecutive naturals, for example, 3718902 + ... + 3718919.

It is an arithmetic number, because the mean of its divisors is an integer number (16115281).

Almost surely, 2^66940389 is an apocalyptic number.

It is an amenable number.

66940389 is a deficient number, since it is larger than the sum of its proper divisors (29751297).

66940389 is a wasteful number, since it uses less digits than its factorization.

66940389 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7437827 (or 7437824 counting only the distinct ones).

The product of its (nonzero) digits is 279936, while the sum is 45.

The square root of 66940389 is about 8181.7106402023. The cubic root of 66940389 is about 406.0343201026.

The spelling of 66940389 in words is "sixty-six million, nine hundred forty thousand, three hundred eighty-nine".