66591663 has 8 divisors (see below), whose sum is σ = 89651328. Its totient is φ = 43963224.

The previous prime is 66591611. The next prime is 66591673. The reversal of 66591663 is 36619566.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 66591663 - 2¹³ = 66583471 is a prime.

It is a super-2 number, since 2×66591663² = 8868899162211138, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66591673) 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 in 7 ways as a sum of consecutive naturals, for example, 107445 + ... + 108062.

It is an arithmetic number, because the mean of its divisors is an integer number (11206416).

Almost surely, 2^66591663 is an apocalyptic number.

66591663 is a deficient number, since it is larger than the sum of its proper divisors (23059665).

66591663 is a wasteful number, since it uses less digits than its factorization.

66591663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 215613.

The product of its digits is 174960, while the sum is 42.

The square root of 66591663 is about 8160.3714988964. The cubic root of 66591663 is about 405.3280134926.

The spelling of 66591663 in words is "sixty-six million, five hundred ninety-one thousand, six hundred sixty-three".