66978016 has 48 divisors (see below), whose sum is σ = 152216064. Its totient is φ = 28416384.

The previous prime is 66978007. The next prime is 66978019. The reversal of 66978016 is 61087966.

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66978019) 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, 21621 + ... + 24523.

It is an arithmetic number, because the mean of its divisors is an integer number (3171168).

Almost surely, 2^66978016 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66978016, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (76108032).

66978016 is an abundant number, since it is smaller than the sum of its proper divisors (85238048).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66978016 is a wasteful number, since it uses less digits than its factorization.

66978016 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3023 (or 3015 counting only the distinct ones).

The product of its (nonzero) digits is 108864, while the sum is 43.

The square root of 66978016 is about 8184.0097751652. The cubic root of 66978016 is about 406.1103827605.

The spelling of 66978016 in words is "sixty-six million, nine hundred seventy-eight thousand, sixteen".