66847680 has 140 divisors (see below), whose sum is σ = 237881160. Its totient is φ = 17819136.

The previous prime is 66847661. The next prime is 66847691. The reversal of 66847680 is 8674866.

It is a happy number.

It is a super-2 number, since 2×66847680² = 8937224642764800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a zygodrome in base 2 and base 4.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 24631 + ... + 27209.

Almost surely, 2^66847680 is an apocalyptic number.

66847680 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 66847680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (118940580).

66847680 is an abundant number, since it is smaller than the sum of its proper divisors (171033480).

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

66847680 is a wasteful number, since it uses less digits than its factorization.

66847680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2608 (or 2589 counting only the distinct ones).

The product of its (nonzero) digits is 387072, while the sum is 45.

The square root of 66847680 is about 8176.0430527242. The cubic root of 66847680 is about 405.8467879435.

The spelling of 66847680 in words is "sixty-six million, eight hundred forty-seven thousand, six hundred eighty".