66317978 has 8 divisors (see below), whose sum is σ = 99511968. Its totient is φ = 33147324.

The previous prime is 66317939. The next prime is 66318013. The reversal of 66317978 is 87971366.

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6425 + ... + 13187.

It is an arithmetic number, because the mean of its divisors is an integer number (12438996).

Almost surely, 2^66317978 is an apocalyptic number.

66317978 is a deficient number, since it is larger than the sum of its proper divisors (33193990).

66317978 is a wasteful number, since it uses less digits than its factorization.

66317978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11668.

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

The square root of 66317978 is about 8143.5850827507. The cubic root of 66317978 is about 404.7719653144.

The spelling of 66317978 in words is "sixty-six million, three hundred seventeen thousand, nine hundred seventy-eight".