66685637 has 2 divisors, whose sum is σ = 66685638. Its totient is φ = 66685636.

The previous prime is 66685631. The next prime is 66685693. The reversal of 66685637 is 73658666.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 54893281 + 11792356 = 7409^2 + 3434^2 .

It is a cyclic number.

It is not a de Polignac number, because 66685637 - 2¹⁸ = 66423493 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 66685591 and 66685600.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66685631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33342818 + 33342819.

It is an arithmetic number, because the mean of its divisors is an integer number (33342819).

Almost surely, 2^66685637 is an apocalyptic number.

It is an amenable number.

66685637 is a deficient number, since it is larger than the sum of its proper divisors (1).

66685637 is an equidigital number, since it uses as much as digits as its factorization.

66685637 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1088640, while the sum is 47.

The square root of 66685637 is about 8166.1274175707. The cubic root of 66685637 is about 405.5185898572.

The spelling of 66685637 in words is "sixty-six million, six hundred eighty-five thousand, six hundred thirty-seven".