66897680 has 40 divisors (see below), whose sum is σ = 159162432. Its totient is φ = 26135424.

The previous prime is 66897679. The next prime is 66897683. The reversal of 66897680 is 8679866.

It is a tau number, because it is divible by the number of its divisors (40).

It is not an unprimeable number, because it can be changed into a prime (66897683) 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, 6284 + ... + 13163.

Almost surely, 2^66897680 is an apocalyptic number.

It is an amenable number.

66897680 is an abundant number, since it is smaller than the sum of its proper divisors (92264752).

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

66897680 is a wasteful number, since it uses less digits than its factorization.

66897680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19503 (or 19497 counting only the distinct ones).

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

The square root of 66897680 is about 8179.1001950092. The cubic root of 66897680 is about 405.9479496799.

The spelling of 66897680 in words is "sixty-six million, eight hundred ninety-seven thousand, six hundred eighty".