66556291 has 2 divisors, whose sum is σ = 66556292. Its totient is φ = 66556290.

The previous prime is 66556283. The next prime is 66556327. The reversal of 66556291 is 19265566.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66556291 - 2³ = 66556283 is a prime.

It is not a weakly prime, because it can be changed into another prime (66556201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33278145 + 33278146.

It is an arithmetic number, because the mean of its divisors is an integer number (33278146).

Almost surely, 2^66556291 is an apocalyptic number.

66556291 is a deficient number, since it is larger than the sum of its proper divisors (1).

66556291 is an equidigital number, since it uses as much as digits as its factorization.

66556291 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 97200, while the sum is 40.

The square root of 66556291 is about 8158.2039077238. The cubic root of 66556291 is about 405.2562337275.

The spelling of 66556291 in words is "sixty-six million, five hundred fifty-six thousand, two hundred ninety-one".