66867920 has 80 divisors (see below), whose sum is σ = 179655168. Its totient is φ = 22671360.

The previous prime is 66867883. The next prime is 66867929. The reversal of 66867920 is 2976866.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66867929) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 53705 + ... + 54935.

Almost surely, 2^66867920 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 66867920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (89827584).

66867920 is an abundant number, since it is smaller than the sum of its proper divisors (112787248).

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

66867920 is a wasteful number, since it uses less digits than its factorization.

66867920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1348 (or 1342 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 44.

The square root of 66867920 is about 8177.2807216091. The cubic root of 66867920 is about 405.8877442892.

The spelling of 66867920 in words is "sixty-six million, eight hundred sixty-seven thousand, nine hundred twenty".