66398817 has 8 divisors (see below), whose sum is σ = 88642624. Its totient is φ = 44210448.

The previous prime is 66398747. The next prime is 66398819. The reversal of 66398817 is 71889366.

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

It is not a de Polignac number, because 66398817 - 2¹¹ = 66396769 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66398819) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10978 + ... + 15915.

It is an arithmetic number, because the mean of its divisors is an integer number (11080328).

Almost surely, 2^66398817 is an apocalyptic number.

It is an amenable number.

66398817 is a deficient number, since it is larger than the sum of its proper divisors (22243807).

66398817 is a wasteful number, since it uses less digits than its factorization.

66398817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27719.

The product of its digits is 435456, while the sum is 48.

The square root of 66398817 is about 8148.5469256794. The cubic root of 66398817 is about 404.9363655547.

The spelling of 66398817 in words is "sixty-six million, three hundred ninety-eight thousand, eight hundred seventeen".