66085819 has 4 divisors (see below), whose sum is σ = 69564040. Its totient is φ = 62607600.

The previous prime is 66085801. The next prime is 66085823. The reversal of 66085819 is 91858066.

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 66085819 - 2⁵ = 66085787 is a prime.

It is a super-2 number, since 2×66085819² = 8734670945801522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66085879) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1739082 + ... + 1739119.

It is an arithmetic number, because the mean of its divisors is an integer number (17391010).

Almost surely, 2^66085819 is an apocalyptic number.

66085819 is a deficient number, since it is larger than the sum of its proper divisors (3478221).

66085819 is a wasteful number, since it uses less digits than its factorization.

66085819 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3478220.

The product of its (nonzero) digits is 103680, while the sum is 43.

The square root of 66085819 is about 8129.3184831202. The cubic root of 66085819 is about 404.2990853784.

The spelling of 66085819 in words is "sixty-six million, eighty-five thousand, eight hundred nineteen".