66858240 has 144 divisors (see below), whose sum is σ = 223106688. Its totient is φ = 17031168.

The previous prime is 66858221. The next prime is 66858247. The reversal of 66858240 is 4285866.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66858247) 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, 87942 + ... + 88698.

It is an arithmetic number, because the mean of its divisors is an integer number (1549352).

Almost surely, 2^66858240 is an apocalyptic number.

66858240 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66858240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (111553344).

66858240 is an abundant number, since it is smaller than the sum of its proper divisors (156248448).

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

66858240 is a wasteful number, since it uses less digits than its factorization.

66858240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 804 (or 790 counting only the distinct ones).

The product of its (nonzero) digits is 92160, while the sum is 39.

The square root of 66858240 is about 8176.6888163853. The cubic root of 66858240 is about 405.8681575030.

The spelling of 66858240 in words is "sixty-six million, eight hundred fifty-eight thousand, two hundred forty".