66399906 has 8 divisors (see below), whose sum is σ = 132799824. Its totient is φ = 22133300.

The previous prime is 66399901. The next prime is 66399911. The reversal of 66399906 is 60999366.

It is an interprime number because it is at equal distance from previous prime (66399901) and next prime (66399911).

It is a sphenic number, since it is the product of 3 distinct primes.

66399906 is an admirable number.

It is not an unprimeable number, because it can be changed into a prime (66399901) 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, 5533320 + ... + 5533331.

It is an arithmetic number, because the mean of its divisors is an integer number (16599978).

Almost surely, 2^66399906 is an apocalyptic number.

66399906 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66399906 is a wasteful number, since it uses less digits than its factorization.

66399906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11066656.

The product of its (nonzero) digits is 472392, while the sum is 48.

The square root of 66399906 is about 8148.6137471352. The cubic root of 66399906 is about 404.9385793154.

The spelling of 66399906 in words is "sixty-six million, three hundred ninety-nine thousand, nine hundred six".