66643200 has 324 divisors, whose sum is σ = 259475580. Its totient is φ = 16220160.

The previous prime is 66643193. The next prime is 66643201. The reversal of 66643200 is 234666.

It can be written as a sum of positive squares in 6 ways, for example, as 15492096 + 51151104 = 3936^2 + 7152^2 .

It is a super-2 number, since 2×66643200² = 8882632212480000, which contains 22 as substring.

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66643201) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 748756 + ... + 748844.

Almost surely, 2^66643200 is an apocalyptic number.

66643200 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 66643200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (129737790).

66643200 is an abundant number, since it is smaller than the sum of its proper divisors (192832380).

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

66643200 is a wasteful number, since it uses less digits than its factorization.

66643200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 134 (or 112 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 27.

The square root of 66643200 is about 8163.5286488136. The cubic root of 66643200 is about 405.4325511192.

Adding to 66643200 its reverse (234666), we get a palindrome (66877866).

The spelling of 66643200 in words is "sixty-six million, six hundred forty-three thousand, two hundred".