66378917 has 8 divisors (see below), whose sum is σ = 73131552. Its totient is φ = 59746000.

The previous prime is 66378911. The next prime is 66378937. The reversal of 66378917 is 71987366.

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

It is a cyclic number.

It is not a de Polignac number, because 66378917 - 2⁴ = 66378901 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66378911) 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, 28763 + ... + 30984.

It is an arithmetic number, because the mean of its divisors is an integer number (9141444).

Almost surely, 2^66378917 is an apocalyptic number.

It is an amenable number.

66378917 is a deficient number, since it is larger than the sum of its proper divisors (6752635).

66378917 is a wasteful number, since it uses less digits than its factorization.

66378917 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59859.

The product of its digits is 381024, while the sum is 47.

The square root of 66378917 is about 8147.3257575722. The cubic root of 66378917 is about 404.8959078116.

The spelling of 66378917 in words is "sixty-six million, three hundred seventy-eight thousand, nine hundred seventeen".