66861600 has 144 divisors (see below), whose sum is σ = 234484992. Its totient is φ = 16450560.

The previous prime is 66861583. The next prime is 66861601. The reversal of 66861600 is 616866.

66861600 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not an unprimeable number, because it can be changed into a prime (66861601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 30129 + ... + 32271.

It is an arithmetic number, because the mean of its divisors is an integer number (1628368).

Almost surely, 2^66861600 is an apocalyptic number.

66861600 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 66861600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (117242496).

66861600 is an abundant number, since it is smaller than the sum of its proper divisors (167623392).

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

66861600 is a wasteful number, since it uses less digits than its factorization.

66861600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2179 (or 2166 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 33.

The square root of 66861600 is about 8176.8942759461. The cubic root of 66861600 is about 405.8749564364.

The spelling of 66861600 in words is "sixty-six million, eight hundred sixty-one thousand, six hundred".