66424399 has 4 divisors (see below), whose sum is σ = 69920440. Its totient is φ = 62928360.

The previous prime is 66424381. The next prime is 66424411. The reversal of 66424399 is 99342466.

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 66424399 - 2¹⁷ = 66293327 is a prime.

It is a super-3 number, since 3×66424399³ (a number of 24 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66424199) 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 3 ways as a sum of consecutive naturals, for example, 1747992 + ... + 1748029.

It is an arithmetic number, because the mean of its divisors is an integer number (17480110).

Almost surely, 2^66424399 is an apocalyptic number.

66424399 is a deficient number, since it is larger than the sum of its proper divisors (3496041).

66424399 is a wasteful number, since it uses less digits than its factorization.

66424399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3496040.

The product of its digits is 279936, while the sum is 43.

The square root of 66424399 is about 8150.1165022348. The cubic root of 66424399 is about 404.9883632281.

The spelling of 66424399 in words is "sixty-six million, four hundred twenty-four thousand, three hundred ninety-nine".