66559819 has 4 divisors (see below), whose sum is σ = 66591640. Its totient is φ = 66528000.

The previous prime is 66559813. The next prime is 66559837. The reversal of 66559819 is 91895566.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 66559819 - 2⁹ = 66559307 is a prime.

It is a super-2 number, since 2×66559819² = 8860419010625522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66559813) 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, 12534 + ... + 17035.

It is an arithmetic number, because the mean of its divisors is an integer number (16647910).

Almost surely, 2^66559819 is an apocalyptic number.

66559819 is a deficient number, since it is larger than the sum of its proper divisors (31821).

66559819 is a wasteful number, since it uses less digits than its factorization.

66559819 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31820.

The product of its digits is 583200, while the sum is 49.

The square root of 66559819 is about 8158.4201289220. The cubic root of 66559819 is about 405.2633941763.

The spelling of 66559819 in words is "sixty-six million, five hundred fifty-nine thousand, eight hundred nineteen".