66678840 has 96 divisors (see below), whose sum is σ = 226156320. Its totient is φ = 17005824.

The previous prime is 66678827. The next prime is 66678877. The reversal of 66678840 is 4887666.

It is a happy number.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4254 + ... + 12306.

It is an arithmetic number, because the mean of its divisors is an integer number (2355795).

Almost surely, 2^66678840 is an apocalyptic number.

66678840 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 66678840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (113078160).

66678840 is an abundant number, since it is smaller than the sum of its proper divisors (159477480).

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

66678840 is a wasteful number, since it uses less digits than its factorization.

66678840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8093 (or 8086 counting only the distinct ones).

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

The square root of 66678840 is about 8165.7112366284. The cubic root of 66678840 is about 405.5048117603.

The spelling of 66678840 in words is "sixty-six million, six hundred seventy-eight thousand, eight hundred forty".