66563191 has 4 divisors (see below), whose sum is σ = 66908272. Its totient is φ = 66218112.

The previous prime is 66563179. The next prime is 66563221. The reversal of 66563191 is 19136566.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19136566 = 2 ⋅9568283.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66563191 is a prime.

It is a super-2 number, since 2×66563191² = 8861316792204962, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66563191.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66563491) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 172251 + ... + 172636.

It is an arithmetic number, because the mean of its divisors is an integer number (16727068).

Almost surely, 2^66563191 is an apocalyptic number.

66563191 is a deficient number, since it is larger than the sum of its proper divisors (345081).

66563191 is a wasteful number, since it uses less digits than its factorization.

66563191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 345080.

The product of its digits is 29160, while the sum is 37.

The square root of 66563191 is about 8158.6267839631. The cubic root of 66563191 is about 405.2702377700.

The spelling of 66563191 in words is "sixty-six million, five hundred sixty-three thousand, one hundred ninety-one".