66801280 has 256 divisors, whose sum is σ = 208373760. Its totient is φ = 19906560.

The previous prime is 66801263. The next prime is 66801289. The reversal of 66801280 is 8210866.

It is a super-2 number, since 2×66801280² = 8924822019276800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is not an unprimeable number, because it can be changed into a prime (66801289) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1805422 + ... + 1805458.

It is an arithmetic number, because the mean of its divisors is an integer number (813960).

Almost surely, 2^66801280 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 66801280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (104186880).

66801280 is an abundant number, since it is smaller than the sum of its proper divisors (141572480).

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

66801280 is a wasteful number, since it uses less digits than its factorization.

66801280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107 (or 95 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 31.

The square root of 66801280 is about 8173.2050017114. The cubic root of 66801280 is about 405.7528647155.

It can be divided in two parts, 66801 and 280, that added together give a square (67081 = 259²).

The spelling of 66801280 in words is "sixty-six million, eight hundred one thousand, two hundred eighty".