66693680 has 40 divisors (see below), whose sum is σ = 156117984. Its totient is φ = 26496000.

The previous prime is 66693673. The next prime is 66693689. The reversal of 66693680 is 8639666.

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 (66693689) 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, 9320 + ... + 14840.

Almost surely, 2^66693680 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 66693680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (78058992).

66693680 is an abundant number, since it is smaller than the sum of its proper divisors (89424304).

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

66693680 is a wasteful number, since it uses less digits than its factorization.

66693680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5685 (or 5679 counting only the distinct ones).

The product of its (nonzero) digits is 279936, while the sum is 44.

The square root of 66693680 is about 8166.6198638115. The cubic root of 66693680 is about 405.5348924927.

The spelling of 66693680 in words is "sixty-six million, six hundred ninety-three thousand, six hundred eighty".