66539633 has 2 divisors, whose sum is σ = 66539634. Its totient is φ = 66539632.

The previous prime is 66539623. The next prime is 66539677. The reversal of 66539633 is 33693566.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 62283664 + 4255969 = 7892^2 + 2063^2 .

It is a cyclic number.

It is not a de Polignac number, because 66539633 - 2¹⁸ = 66277489 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (66539623) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33269816 + 33269817.

It is an arithmetic number, because the mean of its divisors is an integer number (33269817).

Almost surely, 2^66539633 is an apocalyptic number.

It is an amenable number.

66539633 is a deficient number, since it is larger than the sum of its proper divisors (1).

66539633 is an equidigital number, since it uses as much as digits as its factorization.

66539633 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 262440, while the sum is 41.

The square root of 66539633 is about 8157.1829083330. The cubic root of 66539633 is about 405.2224211381. Note that the first 3 decimals are identical.

The spelling of 66539633 in words is "sixty-six million, five hundred thirty-nine thousand, six hundred thirty-three".