66600000 has 252 divisors, whose sum is σ = 245054628. Its totient is φ = 17280000.

The previous prime is 66599989. The next prime is 66600029. The reversal of 66600000 is 666.

It can be written as a sum of positive squares in 6 ways, for example, as 41679936 + 24920064 = 6456^2 + 4992^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.

It is a nialpdrome in base 10.

It is a zygodrome in base 10.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 1799982 + ... + 1800018.

It is an arithmetic number, because the mean of its divisors is an integer number (972439).

Almost surely, 2^66600000 is an apocalyptic number.

66600000 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 66600000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (122527314).

66600000 is an abundant number, since it is smaller than the sum of its proper divisors (178454628).

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

66600000 is an equidigital number, since it uses as much as digits as its factorization.

66600000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80 (or 47 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

The square root of 66600000 is about 8160.8823052413. The cubic root of 66600000 is about 405.3449279155.

Adding to 66600000 its reverse (666), we get a palindrome (66600666).

66600000 divided by its reverse (666) gives a 5-th power (100000 = 10⁵).

The spelling of 66600000 in words is "sixty-six million, six hundred thousand".