66978068 has 6 divisors (see below), whose sum is σ = 117211626. Its totient is φ = 33489032.

The previous prime is 66978031. The next prime is 66978071. The reversal of 66978068 is 86087966.

It can be written as a sum of positive squares in only one way, i.e., 66552964 + 425104 = 8158^2 + 652^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8372255 + ... + 8372262.

It is an arithmetic number, because the mean of its divisors is an integer number (19535271).

Almost surely, 2^66978068 is an apocalyptic number.

It is an amenable number.

66978068 is a deficient number, since it is larger than the sum of its proper divisors (50233558).

66978068 is a wasteful number, since it uses less digits than its factorization.

66978068 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16744521 (or 16744519 counting only the distinct ones).

The product of its (nonzero) digits is 870912, while the sum is 50.

The square root of 66978068 is about 8184.0129520914. The cubic root of 66978068 is about 406.1104878583.

The spelling of 66978068 in words is "sixty-six million, nine hundred seventy-eight thousand, sixty-eight".