66918320 has 120 divisors (see below), whose sum is σ = 185662224. Its totient is φ = 22353408.

The previous prime is 66918317. The next prime is 66918329. The reversal of 66918320 is 2381966.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is not an unprimeable number, because it can be changed into a prime (66918329) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 168362 + ... + 168758.

Almost surely, 2^66918320 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 66918320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (92831112).

66918320 is an abundant number, since it is smaller than the sum of its proper divisors (118743904).

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

66918320 is a wasteful number, since it uses less digits than its factorization.

66918320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 467 (or 454 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 35.

The square root of 66918320 is about 8180.3618501873. The cubic root of 66918320 is about 405.9896945462.

The spelling of 66918320 in words is "sixty-six million, nine hundred eighteen thousand, three hundred twenty".