66978304 has 20 divisors (see below), whose sum is σ = 133826814. Its totient is φ = 33488896.

The previous prime is 66978299. The next prime is 66978311. The reversal of 66978304 is 40387966.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 41576704 + 25401600 = 6448^2 + 5040^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64897 + ... + 65920.

Almost surely, 2^66978304 is an apocalyptic number.

66978304 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

66978304 is a deficient number, since it is larger than the sum of its proper divisors (66848510).

66978304 is an equidigital number, since it uses as much as digits as its factorization.

66978304 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 130835 (or 130819 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 43.

The square root of 66978304 is about 8184.0273704332. The cubic root of 66978304 is about 406.1109648401.

The spelling of 66978304 in words is "sixty-six million, nine hundred seventy-eight thousand, three hundred four".