66878220 has 48 divisors (see below), whose sum is σ = 189836640. Its totient is φ = 17588736.

The previous prime is 66878183. The next prime is 66878239. The reversal of 66878220 is 2287866.

66878220 is digitally balanced in base 9, because in such base it contains all the possibile digits an equal number of times.

66878220 is strictly pandigital in base 9.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3255 + ... + 12014.

It is an arithmetic number, because the mean of its divisors is an integer number (3954930).

Almost surely, 2^66878220 is an apocalyptic number.

66878220 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

66878220 is an abundant number, since it is smaller than the sum of its proper divisors (122958420).

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

66878220 is a wasteful number, since it uses less digits than its factorization.

66878220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15354 (or 15352 counting only the distinct ones).

The product of its (nonzero) digits is 64512, while the sum is 39.

The square root of 66878220 is about 8177.9104910729. The cubic root of 66878220 is about 405.9085835254.

The spelling of 66878220 in words is "sixty-six million, eight hundred seventy-eight thousand, two hundred twenty".