66640237 has 2 divisors, whose sum is σ = 66640238. Its totient is φ = 66640236.

The previous prime is 66640229. The next prime is 66640253. The reversal of 66640237 is 73204666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 66113161 + 527076 = 8131^2 + 726^2 .

It is a cyclic number.

It is not a de Polignac number, because 66640237 - 2³ = 66640229 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66640267) 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, 33320118 + 33320119.

It is an arithmetic number, because the mean of its divisors is an integer number (33320119).

Almost surely, 2^66640237 is an apocalyptic number.

It is an amenable number.

66640237 is a deficient number, since it is larger than the sum of its proper divisors (1).

66640237 is an equidigital number, since it uses as much as digits as its factorization.

66640237 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 36288, while the sum is 34.

The square root of 66640237 is about 8163.3471689008. The cubic root of 66640237 is about 405.4265424319.

The spelling of 66640237 in words is "sixty-six million, six hundred forty thousand, two hundred thirty-seven".