66856320 has 256 divisors, whose sum is σ = 244555200. Its totient is φ = 17252352.

The previous prime is 66856319. The next prime is 66856351. The reversal of 66856320 is 2365866.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 915804 + ... + 915876.

Almost surely, 2^66856320 is an apocalyptic number.

66856320 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 66856320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (122277600).

66856320 is an abundant number, since it is smaller than the sum of its proper divisors (177698880).

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

66856320 is a wasteful number, since it uses less digits than its factorization.

66856320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 154 (or 136 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The square root of 66856320 is about 8176.5714086040. The cubic root of 66856320 is about 405.8642722959.

It can be divided in two parts, 66856 and 320, that added together give a palindrome (67176).

The spelling of 66856320 in words is "sixty-six million, eight hundred fifty-six thousand, three hundred twenty".