66591673 has 2 divisors, whose sum is σ = 66591674. Its totient is φ = 66591672.

The previous prime is 66591611. The next prime is 66591773. The reversal of 66591673 is 37619566.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 60793209 + 5798464 = 7797^2 + 2408^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66591673 is a prime.

It is not a weakly prime, because it can be changed into another prime (66591773) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33295836 + 33295837.

It is an arithmetic number, because the mean of its divisors is an integer number (33295837).

Almost surely, 2^66591673 is an apocalyptic number.

It is an amenable number.

66591673 is a deficient number, since it is larger than the sum of its proper divisors (1).

66591673 is an equidigital number, since it uses as much as digits as its factorization.

66591673 is an evil number, because the sum of its binary digits is even.

The product of its digits is 204120, while the sum is 43.

The square root of 66591673 is about 8160.3721116135. The cubic root of 66591673 is about 405.3280337819.

The spelling of 66591673 in words is "sixty-six million, five hundred ninety-one thousand, six hundred seventy-three".