66664791 has 12 divisors (see below), whose sum is σ = 96833880. Its totient is φ = 44193840.

The previous prime is 66664789. The next prime is 66664813. The reversal of 66664791 is 19746666.

It is a happy number.

It is not a de Polignac number, because 66664791 - 2¹ = 66664789 is a prime.

It is a super-3 number, since 3×66664791³ (a number of 24 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66664751) 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 11 ways as a sum of consecutive naturals, for example, 19080 + ... + 22301.

It is an arithmetic number, because the mean of its divisors is an integer number (8069490).

Almost surely, 2^66664791 is an apocalyptic number.

66664791 is a deficient number, since it is larger than the sum of its proper divisors (30169089).

66664791 is a wasteful number, since it uses less digits than its factorization.

66664791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41566 (or 41563 counting only the distinct ones).

The product of its digits is 326592, while the sum is 45.

The square root of 66664791 is about 8164.8509478128. The cubic root of 66664791 is about 405.4763302747.

The spelling of 66664791 in words is "sixty-six million, six hundred sixty-four thousand, seven hundred ninety-one".