66442400 has 108 divisors (see below), whose sum is σ = 170641422. Its totient is φ = 25259520.

The previous prime is 66442391. The next prime is 66442403. The reversal of 66442400 is 424466.

It can be written as a sum of positive squares in 3 ways, for example, as 42667024 + 23775376 = 6532^2 + 4876^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 66442400.

It is not an unprimeable number, because it can be changed into a prime (66442403) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 423122 + ... + 423278.

Almost surely, 2^66442400 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66442400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (85320711).

66442400 is an abundant number, since it is smaller than the sum of its proper divisors (104199022).

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

66442400 is a wasteful number, since it uses less digits than its factorization.

66442400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 223 (or 187 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 26.

The square root of 66442400 is about 8151.2207674679. The cubic root of 66442400 is about 405.0249438480.

Adding to 66442400 its reverse (424466), we get a palindrome (66866866).

The spelling of 66442400 in words is "sixty-six million, four hundred forty-two thousand, four hundred".